kimchi & kraut

Passive House + Zero Net Energy + Permaculture Yard

Attic Access Hatch (Air Sealing #7 )

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Our attic is designed mainly to hold our blown-in insulation (a future post will go over the details), as opposed to a place for running HVAC equipment, conduit for electric, or as a potential area for carving out additional storage space.

Nevertheless, in order to have access to our attic for future maintenance or repairs, I installed a well-insulated attic hatch in our master bedroom closet ceiling.

Following Passive House and Pretty Good House principles required trying to protect the thermal envelope, even in this relatively small area, in order to avoid what can be a notorious point of air leakage and heat loss (i.e., the stack effect).

There were two main products I considered using for this:

Battic Door (R-50 / without ladder)

They also have a product that allows for a built-in ladder for easier access to the attic (you won’t need to drag your ladder in from the garage) while also maintaining a high R-value:

Battic Stair Cover

The other product I considered using was from ESS Energy Products:

Energy Guardian Push Up Hatch Cover

We ended up going with the Battic product, which I purchased through the Home Depot website (this saved me a trip to the store since it was delivered to site).

 

 

Some other products that I’m aware of include:

475 High Performance Building Supply used to sell a Passive House certified version with a fold-down ladder included, but I don’t currently see it listed on their website:

WIPPRO Klimatec 160

Or this product that also incorporates a ladder is available from Conservation Technology:

Attic Ladder

Because the Energy Guardian hatch is made out of rigid foam, I thought the Battic door was the better choice since it seemed like it would be a little sturdier and more durable. To be honest, once the product arrived and I unpacked it, I realized it was something I, or anyone with basic carpentry skills, could put together themselves (assuming you have the time).

Following the directions, I cut an X in the Intello on the ceiling between two roof trusses (and our 2×6 service core below each truss) in order to establish the opening for the Battic frame.

I folded the cut edges of Intello up into the attic for the two long sides of the Battic frame. For the two shorter sides of the Battic frame it was easier for air sealing to push the Intello down into the living area.

At this point I was able to screw the Battic frame into place.

looking up into battic attic hatch

Battic frame initially installed between roof trusses and 2×6 service core.

Once in place, I used a mix of Contega HF Sealant and Tescon Vana tape to air seal the Intello to the Battic frame.

battic - taped sealed to intello

Air sealing the Intello to the Battic frame (short side between trusses).

 

tescon vana air sealed battic w: HF behind Intello

Another view of the Intello sealed to the Battic frame.

 

looking down at air sealed battic from attic

View of the installed Battic frame from the attic.

 

attic access air sealed - attic side

Air sealing the connections between the Intello, the Battic frame, and the roof trusses in the attic.

 

air sealed corner of battic

Using HF Sealant to make the connections as air tight as possible.

Once the outside perimeter of the Battic frame had been air sealed to the Intello, the only place left for air infiltration was where the lid would meet the frame of the Battic hatch once it was installed (more on this later when I discuss my first blower door test).

There was some additional framing required, but it was just a couple of “headers” between the roof trusses to add structural integrity to the two shorter sides of the Battic frame.

attic access from below

Battic frame with additional 2×6’s on one of the short sides.

Since we were using a significant amount of blown-in insulation in the attic, it made it necessary to build up the sides of the Battic frame in the attic with some plywood to get the top of the opening above where the insulation would eventually stop.

 

 

 

 

Here’s another view of the 3 sides of plywood installed:

attic access looking down - directly

The fourth and final side of plywood was installed just prior to blowing in the insulation — in the interim this made getting in and out of the attic much easier.

After a couple of practice attempts, it quickly became apparent that raising and removing the lid once in place, and fighting to get it back down into the master bedroom closet, wasn’t worth the trouble. Instead, I built a small bench in the attic next to the Battic frame so I could push the lid up above the level of blown-in insulation, this way it could have somewhere to safely sit while dealing with any issue in the attic.

bench for attic access lid

Battic lid resting on the bench.

It’s very easy to grab the lid off the bench and bring it back down into position while slowly walking down the ladder in the master bedroom closet to make the final connection/seal.

Although the installation process was fairly straightforward and headache free for the Battic product, if I had it to do over, I think I would have the attic access point on the exterior of the structure, for example, on the gable end of the house in the backyard.

GBA – gable access to attic

Custom Gable Vents

AZdiy

Putting the access point above the air barrier would make meticulously air sealing the entry point for the attic less important, so keeping water out of the attic would be the main goal. An additional plywood buck would’ve been necessary, replicating what I did for our windows and doors (more on this later), but I think it still would’ve been the better option overall.

Putting the attic access on the exterior of the house would also mean avoiding an ugly hole somewhere in our drywalled ceiling. No matter how nicely trimmed out, these attic access points on the interior of a home never look right to me. We’ve tried to hide ours as much as possible by sticking it in our master bedroom closet, which has worked out well, but not having one at all on the interior of the house would make for a cleaner, better solution in my opinion.

If granted a do-over, I would also add a cat walk in the attic, through the roof trusses, in order to make getting to any point in the attic much easier to navigate, when necessary in the future, while also avoiding disturbing the blown-in insulation too much.

And here’s a photo of the bench in the attic, next to the opening for the Battic attic hatch, after the blown-in insulation was installed:

bench surrounded by cellulose

Bench for the Battic hatch lid.

WRB: Zip Sheathing (Air Sealing #6 )

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Zip: Air Sealing the Seams and Penetrations

( Note: This post will concentrate on the Zip sheathing itself, as it relates to seams and penetrations. I’ll address how I sealed around openings for windows and doors, along with our attic access hatch through the Intello on the ceiling in separate, future blog posts.)

We used Zip sheathing as our WRB (water-resistant barrier — or sometimes it’s referred to as a weather-resistant barrier) based largely on Hammer and Hand projects,

and seeing it used on various jobs featured in Fine Homebuilding Magazine.

As the 7/16″ Zip sheathing went up, I taped most of the seams with Pro Clima’s  3″ Tescon Vana tape (available at 475 HPBS), but also their Contega tape (6″ wide), which I used mainly for outside corners and larger seams in the Zip (mainly where the horizontal seam in the Zip transitioned from the exterior walls of 2×6 framing to the roof trusses — shown in a photo later in this post).

My wife and daughter also cut up the Tescon Vana tape into small pieces in order to cover all the nail and screw holes in the Zip sheathing.

beast and eduardo taping nail holes

The Beast and Eduardo team up to tape the nail and screw holes on the lower sections of Zip sheathing around the house.

The nail holes were initially sealed with HF Sealant, also available from 475 HPBS, thus giving them double coverage — this was discussed earlier, here:

Framing (Air Sealing #2)

north side house garage gap long view

Northeast corner of the house where it meets the garage.

Our decision to use the Zip sheathing was also discussed earlier, here:

Wall Assembly

And here’s a good video discussing the Zip sheathing and its benefits (and its place in the evolution of building science):

If I had it to do over, I think I might be tempted to use 1/2″ exterior grade plywood as my sheathing (there are any number of WRB options these days). This would be sealed on the exterior side with either a liquid membrane, like Prosoco’s Cat 5, or a peel-n-stick tape like Henry’s Blue Skinor even another 475 HPBS product Solitex Mento 1000.

The Zip sheathing works, and the exterior green skin held up nicely during construction, even as it sat exposed for nearly 10 months after we fired our GC’s and struggled to keep the project moving forward. Nevertheless, it is little more than glorified OSB, which comes with certain inherent weaknesses.

Matt Risinger does an excellent job of delineating the cost/benefits of using either OSB or CDX plywood as a sheathing material:

 

house-garage-gap-for-4%22-roxul

Garage (at left) house (at right) connection. Gap will eventually be filled with 4″ of Roxul Comfortboard 80.

 

garage-house-gap-2

Closer view of this same garage – house connection. Flashing will cover the bottom of the Zip and then carry over the top of the Roxul that covers the foundation.

 

north-side-seams-taped

View of the north side of the house as Tescon Vana tape air seals the nail holes and the seams in the Zip sheathing.

View of the West facade with Tescon Vana tape, along with the black Contega tape at larger seams (e.g., where the walls meet the roof trusses) and outside corners.

west side being taped

West facade as taping proceeds.

 

taping north side before mechanicals : windows

Northwest corner of the house, transitioning from the Tescon Vana to the black Contega tape at the corner.

 

finishing up seams on west facade

Finishing up some of the final seams in the Zip on the West facade.

Once the Zip was fully installed, it was readily apparent that some of the seams, especially near the base of the first floor where a horizontal seam ran around the entire structure, would need to be tightened up.

Here’s a view looking down on one of these areas where the Zip sheathing did not sit flat against the framing members:

down Zip - out of alignment before 1x4's

Horizontal seam in Zip sheathing refusing to lie flat against the 2×6 framing members.

Using a 1×4 in each stud bay, I was able to pull the seam in the Zip sheathing together. It wasn’t always perfect, but the difference was visibly significant and in most areas well worth the effort.

Placing a 1×4 into position over the seam in the Zip, I would drive a couple of screws towards the exterior.

1x4 in study bay before HF

1×4 used to pull an unruly seam in the Zip sheathing together.

 

screw thru zip for 1x4 in stud bay

Screw from the interior poking outside as it initially gets the 1×4 in place.

Once securely attached from the interior, I went outside and drove several screws into the Zip, both above and below the seam in the Zip, to pull the seam tight to the 1×4. At that point, I could go back inside and remove the two screws that were driven towards the exterior.

In addition to air sealing the exterior side of the Zip sheathing, I also invested some time in air sealing the interior side of the Zip as well. Below is a long view of several stud bays with 1×4’s installed, but before air sealing gaps around the 1×4’s and lower areas of the stud bays with HF Sealant.

stud bays w: 1x4's, before HF

Long view after applying the HF Sealant:

ceiling walls - HF Sealant

Close up of the interior side of the Zip sheathing meeting a 2×6 framing member in a stud bay after applying a thick bead of HF Sealant:

thick bead HF sealant in stud bay

Close up of lower area of a stud bay after air sealing with the HF Sealant (it transitions from a light to darker green as it dries):

stud bay w: 1x4 and HF sealant

1×4 installed and HF sealant applied to all gaps and screw/nail holes in the stud bay.

I held off on using the HF Sealant at the wall sill plate/subfloor connection until just prior to installing the Intello on the walls since this area constantly attracts dirt and debris.

Sealing on the interior side with HF Sealant, even between vertical framing members, means that even if there are any weaknesses in either the Zip sheathing or the Tescon Vana tape at these points, air won’t find an easy way in, since it will be blocked from the interior side as well (there won’t be a difference in air pressure to help the outdoor air make its way indoors).

This kind of redundancy in air sealing should give the house long-term protection against air leaks, thereby aiding the long-term durability of the structure, as well as making it a much more comfortable environment to live in.

interior walls sealed w: HF sealant

Using HF Sealant between vertical framing members.

I also spent some time on the roof trusses, sealing around nails, the top plates of the exterior walls, and the many Zip-framing member connections in what will eventually be the attic.

sitting on roof trusses sealing

Sealing around fasteners and framing in the attic with HF Sealant.

This had less to do with air sealing and more to do with preventing any potential water intrusion since this area is technically above our ceiling air barrier (the Intello), which is detailed here:

Ceiling Details (Air Sealing #4)

 

 

 

Inventory of Penetrations through the Zip Air Barrier

I made a mock wall assembly before construction began, which I discussed here:

Wall Assembly

This proved helpful when explaining to the various subs how to help me protect the air barrier — especially when it came time to drill holes through the Zip sheathing. Of particular importance was making holes closer to the center of a stud bay, as opposed to hugging a corner or side of one of the 2×6 framing members. A hole cut too close to a stud or a roof truss is much harder to properly air seal.

bad-good-mock-wall-assembly-for-penetrations

Interior side of our mock wall assembly, showing how all penetrations through the Zip should be in the middle of our framing members. Our original plumber was the only trade that managed to screw this up (it’s no coincidence that he was also the only sub that we had to fire).

In effect, any time a sub had to make a penetration through the air barrier we discussed the details, and once the cut was made I immediately air sealed the penetration both on the exterior and interior side.

By sealing each hole in the Zip on both sides, again I hope it ensures the long-term durability of the overall structure. The main argument for this strategy assumes the exterior side of the sheathing will face more extreme temperatures, and fluctuations in humidity, and presumably even wind-drive rain if/when it gets past the siding and 4″ of Roxul insulation, putting it at greater risk of failure (especially in the long term). By taking the time to air seal the interior side, it just gives the overall air barrier, and therefore the structure, a better chance at avoiding air and water intrusion (that’s the goal anyway).

For air sealing I used a mix of tapes, HF sealant (later even some Prosoco products), EPDM Roflex gaskets, and duct seal.

The penetrations for electric service were my first go at using the Roflex gaskets.

John & Donny installing meter

John and Danny, from Chicago Electric, installing the electric meter.

The smaller diameter Roflex gasket comes with its own Tescon Vana tape, which makes installation straightforward.

close up meter thru Zip w: TVana gaskets

Electric meter with Tescon Vana – Roflex gaskets installed.

 

meter - hole, t. vana prior to appl.

Exterior view of electric Meter air sealed with gaskets and Tescon Vana tape:

electric meter close up gasket : t. vana

Once sealed on the exterior side, I went inside to seal the penetrations for a second time.

meter to panel - interior

Air sealing the electric meter on the interior side.

It was a big moment when the electric panel went in.

main panel in - progress

The house is ready for power.

The installation of our solar panels required air sealing two penetrations — one through the Intello on the ceiling on the inside of the structure, along with one exterior penetration through the Zip:

 

 

 

 

Details regarding the installation of our Solar array can be found here:

Solar on the Roof

corrected solar on:off

Solar disconnect (on/off) with its Tescon Vana gasket.

We also had two frost-free hose bibs, or sill cocks installed, which also required gaskets on the exterior and interior sides of the Zip sheathing.

hosebib w: gasket

Frost free hose bib with gasket.

One of the big advantages a Roflex gasket has over using a sealant like the green HF Sealant, or Prosoco’s Joint and Seam, is the pipe can be moved in and out even after air sealing, which is especially helpful for installing siding later.

We left the sill cocks loose (unconnected inside the house), allowing the siding guys to adjust in and out for a more precise fit of the charred cedar siding.

Below is an example of what conduit through the Zip sheathing looks like before it gets a gasket and tape:

exterior light conduit before gasket

Penetration for conduit before gasket.

And here’s the conduit after the gasket and tape.

gasket for exterior light

Conduit after gasket.

Note the extended length of the conduit, anticipating our 4″ of Roxul covering the Zip, 2-layers of furring strips (vertical then horizontal — for vertically oriented siding), and the eventual charred cedar siding.

The photo below shows the penetrations, along with multiple lines of conduit, for our eventual ductless mini-split Mitsubishi heat pump system. The empty hole will be our disconnect for the heat pump. I’ll go into the details of our ductless mini-split system in a future post.

conduit for heat pumps

Penetrations for our Mitsubishi heat pump system.

Same series of conduit pipes after gaskets and being connected to the compressor outside:

heat pump electric w: t. vana before disconnect

In addition to the conduit for electrical hook-up, the Mitsubishi heat pump system required a separate penetration for running the refrigerant lines to the compressor.

hole in Zip for heat pump pvc

Hole cut for the heat pump refrigerant lines.

After discussing it with Mike from Compass Heating and Air, who did our ductless mini-split installation, we decided to use a 4″ section of PVC plumbing pipe as our “conduit” for running the refrigerant lines from the interior of the structure to the outside.

heat pump - pvc pipe in hole for lines

4″ PVC plumbing pipe for the refrigerant lines.

After the PVC was passed through the hole in the Zip, we added a 2×4 underneath it to give it some added stability, along with the usual gasket and tape for air sealing around the PVC pipe.

heat pump - int side - pvc, gasket, 2x4

Before applying Tescon Vana around the Roflex gasket.

Once the refrigerant lines were passed through the PVC pipe, it was clear that some additional air sealing was required.

gaps around pvc lines before duct seal

PVC pipe with refrigerant lines installed.

I filled the gaps around the refrigerant lines from the interior and exterior sides with duct seal. Before stuffing in the duct seal at either side of the PVC pipe, I added bits of Roxul Comfortboard 80 into the pipe to try and give added R-value to the interior of the PVC pipe (hoping to prevent any possible condensation from forming inside the pipe).

duct seal label

A real life saver when it comes to air sealing. Readily available at big box stores, or online at Amazon.

Duct seal proved especially helpful at air sealing multiple weak points in the structure —areas that would’ve been difficult or impossible to air seal with just tape, gaskets, or sealants.

heat pump pvc w: duct seal close up interior

Using duct seal to block off air from the interior side.

 

heat pump pvc w: gasket before t. vana close up

Another view of the PVC pipe with duct seal.

 

heat pump refrigerant lines - int. leaving basement

The refrigerant lines transitioning from the basement ceiling to the PVC pipe before leaving the structure.

Once the interior was taken care of, I was able to address the exterior side of the PVC pipe:

heat pump lines before tape after duct seal

Exterior view of the PVC pipe with heat pump refrigerant lines exiting the structure, being air sealed with a Roflex gasket and duct seal inside the pipe.

Again, note that the PVC pipe is extended out in preparation for the layers of exterior insulation, furring strips, and siding.

heat pump lines leaving house - sealed

Same area after completing the air sealing with Tescon Vana tape.

And here’s a view of the same area after the siding was installed (I’ll go into the many details regarding the installation of the exterior insulation, furring strips, and siding in a later post).

Heat pump lines w: duct seal and siding

Air sealing for the refrigerant lines complete after the siding is installed.

Additional areas where the duct seal proved to be invaluable:

close up exterior outlet box w: duct seal

Exterior electrical boxes for lights and outlets.

Conduit for the water meter in the basement (only the interior is shown below, but the conduit was air sealed with duct seal on the exterior end as well):

 

 

 

And here’s the same conduit for the water meter as it leaves the house on the first floor:

conduit for water meter sealed w: tape:gasket

Conduit for the water meter, air sealed on both sides of the Zip with the Roflex/Tescon Vana gasket.

I also had to address the disconnect boxes for our solar array and our heat pump. For instance, here’s our solar disconnect box when it’s open:

solar disconnect before removing

And here it is after removing the pull out switch, revealing an air leak:

solar disconnect before duct seal

Close up of the conduit:

close up solar disconnect before duct seal

An even closer look:

close up penetration in solar box before duct seal

And here it is after being air sealed with the duct seal:

close up solar box after duct seal

I did the same air sealing for the Mitsubishi heat pump disconnect box:

heat pump box before removing

Close up of the conduit sealed with the duct seal:

close up penetration in heat pump box w: duct seal

During my initial blower door test (more on that later), some air movement around the main panel in the basement was detected, so when the electrician came back we added duct seal to the main pipe entering the house (it had already been sealed from the exterior side with duct seal):

main panel - interior - duct seal

Close up view of the main panel from the interior where lines first enter the structure.

Besides the penetrations in the Zip sheathing, there were other penetrations through the Intello (our air barrier on the ceiling) that had to be addressed as well. These areas were air sealed with the same set of products as the Zip.

For example, in addition to the conduit for solar through the Intello, we also had to air seal conduit for electric service to the attic (for a light and switch in the attic), in addition to the the penetrations for radon and plumbing waste vents, some of which are shown below:

plumbing vent thru Intello gasket:t. vana

Plumbing waste vent going into the attic.

Another view of this vent pipe after air sealing, this time from below:

sealed plumbing vent from below

Here is one of the vents that our first, incompetent plumber installed too close to one of the 2×6’s used to establish our service core.

plumbing vent installed too close to 2x6

Installed this close to framing makes air sealing the vent needlessly complicated and frustrating.

Here’s the same area after applying the Tescon Vana tape:

plumbing vent too close to 2x6 sealed w: tape

Below is another vent pipe incorrectly installed too close to a 2×6. This one was even more challenging to air seal properly. After the gasket and Tescon Vana, I added the green HF sealant as insurance against air leaks, both for now and in the future.

vent too close w: sealant too

We also had to air seal the penetrations for our Zehnder Comfo-Air 350 ERV ventilation unit. I’ll go into the details of the actual installation later, but here are some photos of the penetrations through the Zip sheathing and how we addressed making them air tight.

ext - comfo pipe going thru zip into basement

First section of Comfo pipe going through the Zip sheathing.

 

Zehnder tube exiting w: gasket

The gray Zehnder Comfo pipe (for supply air stream) exiting the structure with a Roflex gasket.

 

Zehnder pipe sealed w: gasket and tape

Closer view of the Comfo pipe air sealed with a gasket and Tescon Vana tape.

 

close up Zehnder Comfo Pipe w: gasket and t. vana

An even closer view of this same area where pipe meets gasket and tape.

We followed the same process — Roflex gasket, Tescon Vana tape — for the exterior side of the Zehnder Comfo pipe.

ext Zehnder gasket : t. vana

Zehnder Comfo pipe installed, air sealed, and ready for commissioning.

And here’s a picture of both supply and exhaust pipes for the Zehnder.

Zehnder exhaust and supply pipes ext fully sealed

Supply pipe in the background, exhaust in the foreground. The garbage bags keep out weather and animals until after the siding is up and the final covers can be installed.

During my initial blower door test some air movement around the sump pit was detected.

sump pit air sealed

Sump pit lid sealed with duct seal, Roflex gasket with Tescon Vana, and the seam between the pit and lid sealed with Prosoco Air Dam.

The sump pump discharge pipe also needed to be air sealed on both sides of the Zip.

sump discharge pipe w: gasket and joint and seam

Sump discharge pipe sealed first with Prosoco Joint and Seam, then a Roflex gasket, before applying Tescon Vana tape around the gasket.

Some air movement around the ejector pit was also detected, so I used duct seal to try and block it.

ejector pit air sealed with duct seal

Ejector pit air sealed with duct seal.

For low voltage — in our case, a cable TV/Internet connection — we found a utility box at Lowe’s (also available at Home Depot and Amazon), and combined it with conduit to transition from the exterior to the interior. The diameter of the conduit is large enough to allow wires for other utilities/services to pass through as well, if necessary, in the future.

cable box

Cable box installed after the siding went up.

An engineer from Comcast-Xfinity visited the site back in the summer, and he gave me the go-ahead for using this box/conduit set-up.

close up exterior of closed cable box

Closer view of the cable box.

 

cable box ext without cover

The cable wire exiting the house through the conduit, which is air sealed with duct seal.

 

cable wire int. basement

Cable wire on the interior of the house exiting through the Roxul insulation and Zip sheathing via the conduit and then air sealed from the interior with duct seal.

Even the wire for the doorbell was sealed with a gasket and tape.

doorbell gasket and tape

When the weather warmed up I was able to experiment with the Prosoco R-Guard series of products (note the 3/4″ plywood door buck treated with Joint and Seam and Fast Flash). I’ll go into that more when I discuss prepping for the windows and doors later.

 

close up of doorbell gasket

A closer view of the doorbell gasket.

Air sealing the penetrations was challenging at times, but also a lot of fun — always keeping in mind the goal of meeting the Passive House standard of 0.6 ACH for our blower door test.

Convinced of the connection between air tightness and the durability of a structure — not to mention the impact air tightness has on heating and cooling loads (i.e., monthly utility bills) —I wanted to see just how air tight I could get the house.

Hopefully this inventory of penetrations will prove helpful to someone in the planning stages of their own “air tight” build. It always helps to be able to see how other people do things — in particular, the strategies they employ and the specific products they use. Seeing these real world examples of air sealing around the many penetrations in a structure will hopefully give others the confidence to come up with their own plan of attack for building an air tight structure.

Basement Slab (Air Sealing #5)

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The Bottom of our Thermal Envelope

Following Passive House principles, we knew we were going to insulate and air seal our basement slab. As explained on the Passipedia website:

“The most important principle for energy efficient construction is a continuous insulating envelope all around the building… which minimises heat losses like a warm coat. In addition to the insulating envelope, there should also be an airtight layer… as most insulation materials are not airtight. Independently of the construction, materials or building technology, one rule is always applicable: both insulation and airtight layers need to be continuous.”

 

airtightness_with_logo

Illustration courtesy of: passipedia.org

The illustration above also shows the “red pen test”, which is supposed to occur in the design phase of a project, when it’s much easier to address weaknesses or errors in the details of a design — not necessarily just for air sealing, it’s also effective when looking for points of potential water intrusion (e.g., this GBA article), or even to test the thermal layer for areas of thermal bridging. The basic idea is that if your layers aren’t continuous you’ll find yourself lifting your red pen, meaning it’s an area that needs to be addressed.

An effective way of thinking about a structure, utilized by high-performance builders, is to think in terms of 6 sides rather than just 4 when contemplating the details for air sealing and insulating: 4 walls, the attic/roof, and the basement (or frost-protected slab).

A similar approach to Passive House for building high-performance structures is adopted by advocates of The Pretty Good House concept, even if it’s less stringent, more open to interpretation, and tends to be more “rule of thumb” rather than energy model driven (e.g. PHPP or WUFI).

Based on our climate region, which is Zone 5, we decided we wanted to shoot for 16/20/40/60 for insulation R-values — the series of numbers represent R-values for under the basement slab/ the exterior foundation walls/ framed exterior walls/ and the attic (our attic R-value proved to be significantly higher than 60, but more on that later) — which is in the ballpark for both PGH and Passive House (here’s an excellent overall summary of the PH concept I recently came across: EcoCor).

Arguably, the “sweet spot” for how much insulation makes sense for these areas, even when adjusted for climate region, is still a topic for heated debate. Nevertheless, it’s important to keep in mind that the more simple the form your structure takes — for example, 2-story cubes without basements —

the easier it is to achieve Passive House, or similar building standards, since it simplifies framing, air sealing, and limits the exterior surface area in ways that a single story ranch that is spread out and has all kinds of nooks and crannies does not (the difference also has serious ramifications for overall heating and cooling demand). Likewise, simple forms also make it easier to figure out how much insulation you need to reach a benchmark like Passive House or PGH. A simple form can also have durability implications.

Our R-values were based on a number of considerations: the construction drawings of our original builder, information made available by Hammer and Hand (in particular their Madrona House project), and articles on the Building Science Corporation (in particular: 1 and 2) and Green Building Advisor websites. These resources, all of which have proven to be indispensable at every stage of the build, have made our project possible.

In terms of the details around the slab and the foundation walls, this article from the DOE also proved to be especially helpful: Foundation Handbook

2-04_no-cap

Illustration courtesy of: foundation handbook.ornl.gov

After considering various insulation choices (Wall Assembly), we decided to go with Roxul for under our slab, the exterior of our foundation, and our wall assembly (blown-in cellulose in the attic was the only significant deviation from the use of Roxul).

Here’s how the basement slab portion of our project progressed:

 

 

Roxul Comfortboard 80 (2″ + 2″)

To get to an R-value of 16 we used two layers of 2″ thick Roxul Comfortboard 80 (R-4 per inch).

We installed each layer with staggered seams, although the Roxul representative I spoke with via email insisted that because the Roxul is so dimensionally stable this isn’t nearly as important as it would be with rigid foam insulation (the same holds true with a double layer of Comfortboard 80 on the exterior side of wall sheathing).

roxul in basement 2 layers

Putting down the 2 layers of Roxul Comfortboard 80 with help from the concrete guys.

 

roxul long view two layers

The second layer of Roxul being installed.

 

roxul before stego

Installing the Roxul around the rough-in bathroom pipes, sump, and ejector pits.

One of the many benefits of using Roxul is that the material wants to stick to itself, whether in batt or rigid board form. This makes for tighter joints between pieces, and even when cuts around obstructions are less than perfect it’s easy to fill in any gaps with torn apart pieces of Roxul (again, this holds true for both Comfortboard 80 and their version of batt insulation).

roxul stuffed in around basement pole

Stuffing bits of Roxul around the base of one of the steel columns.

Close up of the Roxul installed around the roughed-in bath PVC pipes.

roxul around rough-in bath

Another view of the 2-layers, mostly installed.

roxul before stego - facing ladder

A Roxul rep told me to take into account a loss of R-1 due to the compressive pressure of the poured concrete, thus our R-16 for two layers of Roxul is, according to Roxul, really an R-15. Having installed the two layers myself, walked on it during and after installing the vapor barrier (see below), my guess is in some areas this loss in R-value is even greater than R-1.

Based on the comments quoted in a GBA article (Sub-Slab Mineral Wool), I would have to say my experience was exactly the same: in some areas the Roxul seemed to lose most, if not all, of its rigidity. I’ve also noticed while working with both the Comfortboard 80 and their batts, that there seems to be a variation in the material from piece to piece and bag to bag. Some pieces are very easy to cut (these pieces are noticeably stiffer), while other pieces seem “mushier” or lacking in rigidity — either under or over-cooked perhaps — making them more difficult to cut and work with. This seems like less of an issue for vertical applications (i.e. walls), while potentially troublesome for horizontal applications under a slab — especially if you’re depending on that R-4 per inch to meet the demands of energy modeling for a certification program like Passive House.

I’m glad we’ve been able to mostly avoid foam insulation in the build, but seeing the Roxul in a real world application does make me wonder if some kind of rigid foam might’ve given me a more consistent whole floor R-value.

 

 

Stego Wrap

Once the two layers of Roxul were down, it was time to install the vapor barrier over the insulation. While the Roxul acts like a blanket, helping to maintain a consistent temperature in the basement, the vapor barrier helps to keep moisture and soil gases (mainly Radon as I understand it), at bay.

The product I’ve seen used in most Passive House, Pretty Good House, or equivalent projects, is Stego Wrap. Here are two videos detailing its installation and its benefits:

 

Another product I came across while researching options was Perminator.

Here’s a video detailing the use of the product:

In my area — the suburbs of Chicago — the closest supplier of Stego Wrap was HD Supply.

starting stego around roug-in pipes

Starting around the rough-in bathroom pipes.

We used the 10 mil version of the Stego Wrap. The material is very durable and fairly hard to damage. Even when tears occurred, it was easy to patch with pieces of the Stego red tape, or a combination of a cut piece of Stego Wrap with pieces of the red tape.

stego going down

Stego Wrap carried up the wall and taped to keep it in place.

Installing the two layers of Roxul on the basement floor was pretty straightforward, while installing the Stego Wrap was generally a pain in the ass. Maybe I was just tired, but I really didn’t enjoy installing it at all. For example, it was difficult to keep it tight to the walls, although I learned to leave it hanging fairly loose at floor-wall junctions, which definitely helped. Getting the first row straight, flat, and smooth was time consuming, and annoying, but it did make getting successive rows installed straight much easier.

jesus helping me w: first row stego

Jesus helping me install the first row of Stego Wrap.

 

almost halfway w: stego wrap

Making progress with the Stego Wrap.

 

sealed basement pipe close up before pour

Stego Wrap wth red Stego tape and a Roflex gasket from 475 HPBS.

The pipes after air sealing with EPDM gaskets and red Stego tape:

sealed basement pipes with overlapping Stego

Once all the Stego was in place, we added a 1/2″ of rigid foam insulation at the floor-wall junction as a thermal break. I wanted to use Roxul Comfortboard 80 (their 1.25″ thick version) even for this, but time (Comfortboard 80 is still a special order item in my area, meaning it’s always about 2 weeks away from the time you place your order — hopefully this changes in the near future) and money made the foam an easier choice.

stego w: foam close up

We kept the foam in place by running a bead of OSI sealant on the back of each section before pushing it up against the Stego Wrap. For the most part this seemed to work well.

stego w: foam at slab edge

Roxul, Stego Wrap, and Foam installed.

Here’s a close-up of everything installed in a corner:

stego w: foam at a corner

One of the real disappointments of installing the basement slab was seeing the concrete guys put down the welded wire mesh (typically noted as W.W.M. on construction drawings) — basically chicken wire with pointy ends (I exaggerate, but not by much).

If I could do it over again, I would look into using a concrete mix containing sufficient pieces of fiberglass, or some other alternative, so that using the welded wire mesh could be avoided altogether.

 

I was already familiar with the idea of fiberglass used in place of metal in concrete forms, having experimented with decorative concrete last year and having seen videos like these:

 

I’m not sure why I didn’t think to ask for fiber reinforced concrete instead of the normal welded wire mesh — it was one detail that just got missed, unfortunately.

As the wire mesh went down, the guys could see how annoyed and concerned I was by the holes it was making in the Stego Wrap that one of them, Oscar, started helping me bend the pointy ends up. Once they were safely pointed up, I went around with the red tape to patch the many tiny holes in the Stego Wrap. Not a fun way to kill a couple of hours.

Why my architect or the concrete guys didn’t suggest a mix with fiberglass instead of the welded wire mesh is unclear. The reality with any green build, especially if you’re acting as GC, is you’re likely to be the only one who really cares about getting the many details right, especially if the architect and subcontractors have never built like this before — they were just doing what they always do.

A couple shots of the basement floor with the welded wire mesh in place:

A closer view with all the elements in place prior to the pour:

corner of basement pre-pour

 

 

Concrete

Here’s various shots of the slab itself being poured:

hole in floor for basement slab

It was necessary to cut a hole in the subfloor just inside the front door in order to get the concrete into the basement.

 

concrete going thru floor

 

long view of brace for pour

The guys starting at the back of the basement.

 

leveling back corner of basement

 

back corner of basement pour #2

One corner complete.

 

pour heading towards basement stairwell

 

leveling towards stairwell

 

pour at stairwell

 

Tools at stairwell

 

finishing concrete at stairwell

 

troweling at stairwell

Enrique completing the trowel finish.

 

cement truck kissing corner of garage

Side of the garage kissed by the cement truck.

 

close sewer clean out

Close.

 

close long view sewer

Really close.

 

 

Slab Edge

Once the slab was in place, I wasn’t quite sure how to deal with the edge along the perimeter. As usual when I get stuck on some detail, I asked a question on GBA:

How do I seal…

Stego Wrap and Foam cut away from slab edge

Cutting away the excess Stego Wrap and purple foam.

 

close up of slab edge

Close up of the wall-slab junction after cutting everything down flush with the floor.

Using the Prosoco Air Dam seemed like the best, and most straightforward, option. In addition, after considering various ways to cover this gap after the Air Dam was down between the wall and floor, and after priming and painting the basement walls, I realized the gap visually disappears for the most part, and really wasn’t worth thinking about.

wall-slab connection after air dam.jpg

Junction between wall and slab after using Air Dam and priming and painting the wall.

 

close up of wall - slab conection after air dam

Close up of Air Dam, after primer and paint, at the wall-slab connection.

 

another view slab:wall connection

Another view of the slab – wall connection.

 

By not putting anything down to cover this gap, if the basement ever does experience water damage, it’s one less thing to remove and replace.

Solar on the Roof

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After deciding to pursue a combination of Passive House and The Pretty Good House concepts, which entail careful planning and attention to air sealing, along with a significant amount of insulation, we knew we could have a shot at Net Zero, or Zero Net Energy (ZNE) — meaning we could potentially produce as much energy as we use by utilizing solar panels on the roof.

To find an installer in our area, we utilized the website Energy Sage. In addition to useful articles and information about solar, they also work with installers who can provide consumers with competitive bids. It didn’t happen overnight, but in about a week or two, we ended up with 3-4 bids before deciding to go with Rethink Electric in Geneva, Illinois.

laying out the solar panels pre-install

The guys from Rethink staging the panels on the garage roof.

 

 

The System

Based on the suggestions from Energy Sage and Rethink, we ended up going with the following system:

  • 2.915 kW DC System
  • 4,059 kWh of system production
  • 11 Canadian Solar panels
  • 265W Module Enphase M250 (Microinverter)
  • Also includes web-based monitoring of the system’s production

In theory, this system could produce more energy than we use (it’s just my wife, my daughter, and myself who will be living in the house), particularly if we stick to all LED lighting, use Energy Star rated appliances, the heat pump water heater works as advertised, and we’re careful about avoiding using electricity when it’s unnecessary (e.g. turning off lights after leaving a room, or trying to address phantom loads).

Anthony putting self-adhering gasket over solar conduit penetration

Anthony, from Rethink, air sealing the penetration through the Intello, our ceiling air barrier,  with a Tescon Vana – Roflex gasket before sending his 3/4″ conduit into the attic.

Based on other projects I’ve read about, even homes initially built to the ZNE standard sometimes fail, in terms of overall performance, based on actual occupant behavior, so only time will really tell what impact our solar array will have on our utility bills. It looks like worst case scenario would be needing to add 4-6 more panels to get to ZNE or even carbon positive.

conduit for solar in the attic before gasket

Anthony’s conduit entering the attic, sealed with a gasket from below.

Installation by Rethink went really well, and they were happy to work with me on properly air sealing the conduit that runs from the basement at the main panel before going up into the attic, where it eventually terminates on the roof when connected to the panels.

conduit for solar in the attic after gasket

3/4″ conduit sealed for a second time on the attic side of the Intello.

 

solar mounting system being installed

The guys setting up the racking system for the panels.

 

close up solar base

Close up of the base that’s holding the solar panels.

 

Rethink guys on the roof

Anthony, Dan, and Cherif completing the install on the roof of the house.

 

close up of solar panels being installed

The low profile racking system has a very sleek look.

Marking another big leap in the progress of the build:

solar panels on roof

The view of our 11 solar panels from our neighbor’s driveway.

 

solar panels installed on the roof.jpg

Another view of the solar panels installed on the roof.

It was only after the installation that I realized what’s wrong with the following picture:

solar on:off against Zip sheathing #2

My screw up.

I was so worried about getting the air sealing details right on the interior, from the main floor to the attic, I completely forgot to let Anthony know about extending out his disconnect box 6″ to what will be our finished surface (once two layers of Roxul and two layers of 1×4 furring strips, along with cedar siding are installed). The day after they installed, I came walking around the corner of the house, saw this, and literally slapped my forehead (while spitting out a few choice expletives), as I realized my screw up.

Thankfully, Anthony was able to come back out and make the necessary adjustment:

corrected solar on:off

 

 

The Cost

Here’s the cost breakdown on our system (if trends continue, a similar system should be less expensive in the future):

$12,519.50  Initial Investment
$(-3,755.85)  Federal Tax Credit (ITC) 30%
$8,763.65  Net Cost of First Year
$(-3,816.00)  Solar Renewable Energy Credits (SREC’s)
$4,947.65  Net Cost After All Incentives

It will be interesting to follow the performance of the solar panels over the course of a calendar year or two, just to find out exactly how well they perform. I’ll come back here and post monthly utility statements, noting output of the panels and our use, to give people a better sense of actual performance — hopefully this will help others in the planning stages of their own project to decide if solar (and how much of it) is right for them.

Ceiling Details (Air Sealing #4)

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Installing Intello

We thought about using the Zip sheathing as our air barrier on the ceiling, attaching it to the bottom of the roof trusses, something I had seen on other builds, but after learning about Intello we decided to use that instead:

 

 

Floris Keverling Buisman, from 475 High Performance Buidling Supply, did our WUFI analysis for us, and he suggested the Intello would be a better fit for our project. The Intello is a smart vapor retarder, so it can expand and contract when it’s needed, and it’s obviously less physically demanding to install than the Zip sheathing.

Once the air sealing was complete around the top of our outside perimeter walls, and the insulation chutes had been installed, we were almost ready for the Intello. At the gable ends of the house, one last detail needed to be put in place, circled in red in the picture below:

2x6 on its side

2×6 on its side, circled in red.

By adding this 2×6 on its side, which is in the same plane as the bottom of the roof trusses, it makes it possible to carry the Intello over the transition from the ceiling (under the roof trusses) to the walls (top plates). This is one of those details that is hard to “see” when in the planning, more abstract, and two dimensional phase of designing a structure.

another angle of 2x6 on side

Another view of the 2×6 lying flat in the same plane as the bottom of the roof truss (far left).

Once the trusses were placed on the top of the walls and you start imagining how the Intello will be attached to the ceiling, it becomes much more obvious that something in this space at the gable ends of the house is needed in order to accomplish the transition from the ceiling to the walls.

long view w wdw to front door framing

Marking progress: Ceiling ready for the Intello.

After reading about so many other projects that utilized Intello, it was exciting to unwrap the first box.

unwrapping first box of Intello

Big day: opening the first box of Intello.

The directions are pretty straightforward, and the product is relatively easy to install, as long as you don’t have to do it alone.

Intello instructions

Reading through the instructions one last time before starting.

I didn’t get a chance to touch and feel the product before ordering (always fun to do with any new product), so here are some close-ups of the Intello to give you some sense of what it’s like:

Intello close up front side 2

Front: shiny side of the Intello — this side will be facing the living space.

I was curious about its strength and tried to tear it with various objects, including the cut ends of 2×4’s and the brackets we eventually used to help establish our service core. The material is surprisingly tear resistant, but a utility knife, or a stray sharp edge will cut through it (as our first plumber proved to me with his careless actions — a story for another post).

close up Intello back side

Back: matte side of the Intello — this side will be facing the attic.

Having never used the Intello before, I decided to start small and began by experimenting with it in a corner. Getting the corners fully covered while getting the material to sit flat before applying the blue Tescon Vana tape proved to be the most challenging part of using the Intello.

experimenting w: Intello in corner w: chutes above

Starting in a corner to get a feel for how the material will work.

Here’s two more pictures of the flat 2×6 helping to make the transition from the ceiling to the wall:

In order to attach the Intello to the bottom of the roof trusses, we used the staple gun shown below. Loading it is kind of counter-intuitive (online reviews complain about it not working out of the box, but my guess is — like me — they were trying to load it improperly), but once I figured it out, it ended up working really well, almost never jamming, and it’s very comfortable to hold because it’s so light weight. It should work with any standard air compressor. It was available on Amazon, and in Menards, a local big box store here in the Chicago suburbs.

staple gun

The staple gun we used to attach the Intello to the underside of the roof trusses.

Think you know how to load it?

side view of open staple gun

Staple gun ready for loading.

Guess again.

Instead of loading from the bottom, like all the finish nailers I’ve ever used, the staples load higher up, where the staples exit. And yes, there was quite a bit of swearing as I made the transition from “What the…” to “Ohhhh, now I get it…”.

It didn’t help that there were virtually no instructions on its use, apart from a tiny black sticker with an arrow pointing to where to load it (which, of course, I only noticed after figuring this out).

staple gun open w: staples

Loading the staple gun.

We started with these staples:

close up Arrow staples

But we ended up going with these instead:

close up heavy duty Arrow staples

They seemed to grab better (presumably the sharp ends make a difference), and they sit flatter on a more consistent basis (less time having to go back, or stop, to hammer home proud staples flat).

stapling Intello to ceiling

As we rolled out the Intello, it took some practice to get it to sit taught and flat before stapling.

The dotted lines near the edges of the Intello help you keep the rows straight as you overlap two sheets and progress from one row to the next. The lines also make it easier to maintain a straight line with the Tescon Vana tape (don’t ask me when I realized this latter detail — too embarrassing to admit).

taping Intello along dotted line

Follow the dotted line.

We checked our initial row from above in the attic:

first row of Intello from attic

View from the attic as the first row is installed.

Working our way through the interior walls, especially the bathrooms, was more time consuming and took more effort (I grew to hate those interior bathroom walls — first the Intello, then the service core details described below), but once we were out in the open, the Intello is fairly easy to install.

Intello covering ceiling, chutes in bg

First three rows of Intello as they approach the basement stairwell. Note the insulation chutes in the b.g. in the attic — they took up so much time and effort, and now they slowly disappear (just like most important aspects of infrastructure).

 

northwest corner of air sealed attic w: Intello

View of the Intello from a corner of the attic — note the 2×6, far left, lying flat, that helps the Intello transition from the ceiling to the top of the walls.

 

Intello from attic at outside corner

Another view of the Intello from the attic after installation.

As Eduardo and Jesus rolled out sections of the Intello, I followed, pulling on the Intello a little to help make it sit tight and flat, before stapling.

Eduardo and Jesus helping me put up Intello on ceiling

Eduardo and Jesus giving me a hand installing the Intello.

There were a couple of sections, some of the first ones we installed, that I managed to wrinkle (one, in particular, became problematic during our first blower door test — and, of course, it was in a tight spot around the bathroom shower area), but overall, the installation of the Intello went pretty well. Like most things you do for the first time, we got comfortable and good at it just as we were finishing up.

Eduardo Jesus and full moon night sky in b.g.

Eduardo and Jesus helping me finish up the main areas as a full moon makes the night sky glow outside in the background. It was a long day (longer still for Eduardo since Jesus was talkin’ trash and nonsense all day — they’re football teammates — needless to say, Eduardo has the patience of a saint).

 

Intello from attic w: insulation chutes in bg

View of the Intello from the attic — offering up its 2001: A Space Odyssey glow.

After learning about a project on the 475HPBS website…

Masonry Retrofit

 

… we decided to use the Tescon Vana tape to cover the staples, as well as all the seams, in the Intello. I have no idea what actual impact covering the staples has on air tightness, but visually as you tape over the staples you can see how, if nothing else, it will help the staples resist pulling out under pressure from the eventual blown-in cellulose in the attic.

Even as the build progresses, it’s interesting how details like this pop up, making building “green” a never-ending process of learning something new — someone’s always coming up with a new product or a new way to do things better, faster, or less complicated — which makes the process itself very exciting.

OB applying tape

OB — the Palatine High School legend — the man, the myth, helps me tape over the seams and staples in the Intello. One of the many jobs he’s been kind enough to help me get done. We’d be so far behind schedule without all of his help.

 

on plank

View from above what will be the basement stairwell while installing the Intello on the ceiling.

 

installing Intello on the ceiling around the basement opening

Almost finished installing the Intello — saved the hardest part for last.

This was a nice moment, being able to look back and see the Intello completely installed. It’s almost a shame that we have to cover it with drywall.

Intello on ceiling long view

Intello installed and taped.

 

 

2×6 Service Core

A design goal for the ceiling was to keep mechanicals, like HVAC and electric, on the conditioned side of the ceiling air barrier. By doing this, we avoid having to insulate any ductwork for HVAC, or air sealing and insulating around ceiling lights. In effect, we completely isolate the attic, making its sole purpose (apart from ventilating our “cold roof” assembly) holding our blown-in cellulose insulation (this set-up makes it much easier to air seal the ceiling and get the insulation right — at least based on the projects I’ve read about). In order to do this, we created a service chase, or service core, with 2×6’s:

service chase w: first couple of 2x6's

First couple of 2×6’s going in.

In addition to serving as a space to safely pass mechanicals through, the only other job for the 2×6’s is to hold up the ceiling drywall. The roof trusses, directly above each 2×6, are still carrying the load of the roof and stabilizing the perimeter walls.

Simpson L-Bracket w: fasteners

Simpson bracket and fasteners we used to attach the 2×6’s to the underside of the trusses.

Here’s what the 2×6’s looked like with their brackets once everything was installed.

close up service chase w: bracket-screws

Service core 2×6 with bracket and Simpson SDS bolts.

OB and my wife were invaluable, as they helped me cut and install all the 2×6’s.

We installed the brackets first, before raising up each individual 2×6 to fit against the brackets.

jesus helping me install 2x6's

Jesus helping me install the 2×6’s.

Since the brackets were directly attached and under a roof truss, we were able to keep the 2×6’s fairly straight, even when the board itself was less than perfectly straight.

service chase w: just brackets

Brackets installed before the 2×6’s go up.

A feisty Robin kept trying to set up a nest on our partition wall (our windows and doors aren’t in yet). Apparently she believed we had created an elaborate bird house just for her. It took almost a week before she finally gave up — but not before starting multiple nests in multiple spots along the wall.

bird nest

Robin making one of her many attempts at a nest on our partition wall.

Along the outside walls, at the top of the wall assembly, there was a gap that we utilized for maintaining continuous insulation. This meant there will be no break in our thermal layer going from the blown-in cellulose insulation in the attic to the monolithic layer of Roxul Comfortboard 80 (2″ + 2″) that will be on the exterior side of the Zip sheathing.

trusses - Intello - Roxul

Adding Roxul at the top of our wall.

 

layer of Roxul at top of outside wall

Close up of the Roxul going in on top of the top plates.

 

Intello - Roxul - wall

Another view after the Roxul has been installed.

 

long view from west window w: service core complete

Marking further progress: Intello and 2×6’s installed.

Once the 2×6’s were up, we had to install our pieces of 1×4 in order to prevent the 24″ of blown-in cellulose that will be going into the attic from causing the Intello to sag.

The plans called for the 1×4’s to be installed right after the Intello, but before the 2×6’s, which would have been a lot easier and quicker, but, unfortunately, the GC’s we fired installed the interior walls too high, making this impossible.

Here’s what it should’ve looked like if we could’ve done Intello and then the 1×4’s (photos courtesy of 475 HPBS) before installing the 2×6 service core:

Having no choice but to methodically cut each 1×4 to fit between each set of 2×6’s, OB was nice enough to help me get it done.

close up of partition wall w: service core and 1x4 cross battens

Installing the 1×4’s between the 2×6’s began with some experimentation:

service core w: cross battens and L-brackets

Using L-brackets at first —  it proved too time consuming and expensive.

After experimenting with a finish nailer (too easy to miss and penetrate the Intello), we eventually settled on Deckmate screws. It was definitely a laborious process, but eventually we got into a rhythm and got it done, although we wouldn’t recommend doing it this way — way too time consuming.

ceiling w: 1x4 battens

Completing our service core.

We tried to keep the 1×4’s about 16″ apart, which should prevent any significant sagging in the blown-in cellulose from occurring (I’ll post photos once the cellulose has been put in the attic).

A lot of blood, sweat, and tears have gone into completing this house…

Here’s some proof:

screw got me

A decking screw got me.

In trying to avoid puncturing the Intello, I would hold a couple of fingers on the back side of the 2×6, feeling for any screws that would come through on a bad angle. A couple of times I drove a screw too quickly and paid the price.

looking up at Intello and service core from basement

View of the service core from the basement. Installing the 2×6’s and the 1×4’s also required walking the plank a few more times.

 

installing ceiling w: OB

OB making my life easier as I work on the plank installing the 1×4’s.

 

 

 

Maintaining the Intello After Installation

Unfortunately, there was a delay in getting shingles on our roof, due in large part to our first, disorganized plumber (again, more on this later). Consequently, we were in the awkward position of having our ceiling air barrier and service core all set up, but every time it rained we still had a leaking roof. In most areas, it wasn’t a big deal, but in about a dozen spots rain would collect and, if heavy enough, it would bulge the Intello as the Intello carried the weight of the captured water. To relieve, and ultimately to avoid, this pressure, I cut small slits in the Intello where the rain would consistently collect.

small hole in Intello for rain before shingles

Slit in the Intello to allow rain water to fall through, marked with a red marker for easy identification later.

Once the shingles were finally on, I went back and found all of these slits and taped over them with the Tescon Vana.

Tescon Vana covering hole in Intello

Hole in the Intello covered and air sealed with the Tescon Vana tape.

We also found a couple of weak spots in the Intello as we installed it, and even later, during the installation of the service core. These spots were marked as well, and they, too, got covered with the Tescon Vana tape just for added insurance against air leakage.

imperfection in the Intello marked for Tescon Vana

Weak spot, or imperfection, in the Intello. This got covered with Tescon Vana as well.

After having to fire our GC’s, we couldn’t have kept the project going without the help of family and friends. As awful as some aspects of the build have been, it’s been heartwarming to find people willing to help us see the project through to the end (much more on this later).

2 Cheshire Cats

Couple of Cheshire cats — clearly up to no good — helping us to keep the job site clean.

 

Insulation Baffles vs. Insulation Chutes

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Our structure was designed with a “cold roof”, or ventilated roof assembly. By having continuous ventilation in our north and south soffits, with a ridge vent on the top of our roof, outdoor air can freely enter the soffits and exit out the roof’s ridge vent. The benefits of this set-up are explained in these comprehensive articles:

BSC – Roof Design

All About Attic Venting

FHB Roof Venting

Here is the product we’re going to use in the soffits:

Cor-A-Vent

In order to make this kind of roof assembly work, insulation baffles or insulation chutes are necessary, especially if the attic is going to have any kind of significant amount of insulation, in particular blown-in insulation that could potentially move around and block off the soffit ventilation from the attic, thereby short circuiting air flow from the soffits through the roof’s ridge vent.

When it was time to install the insulation baffles, I assumed I could just go to one of the big box stores and (thankfully for a change) just buy something off the shelf. It didn’t work out that way.

At Home Depot they had Durovent (a foam based insulation baffle) and an AccuVent baffle (black plastic). Both were a disappointment.

I didn’t buy the Durovent — even just seeing it on the shelf and handling it in the store, it looked cheap and unimpressive. It was hard to imagine it holding up under the pressure of any significant amount of blown-in insulation pressing against it.

The AccuVent product Home Depot carried only worked in a straight line (no curve to wrap over the back of the Zip sheathing at the top of the wall assembly), ideal for a cathedral ceiling application. After looking around online, I found this other AccuVent product:

Seeing the video made me think it would be an easy installation, but once I had the product on the job site and tried to install one, the realization hit that they would be a pain to properly air seal, and again, I had concerns about blown-in insulation pressing up against it for years.

AccuVent out of the box

AccuVent on the job site. It’s hard not to look at these foam/plastic baffles, regardless of brand, and not think: “flimsy”.

Here’s the specific product info:

AccuVent label close up

And here are the installation instructions:

AccuVent install label

When I realized the AccuVent wasn’t right for our project, it was a moment of, “Uh-oh, now what the hell do I do?”

I assumed there must be a sturdier plastic baffle, but I never found one. Instead, I came across this article:

Site Built Baffles

As usual, old reliable — GBA — had already addressed the issue.

It was nice to have a solution, but I also knew it would be time consuming and back breaking (also neck straining) — the only thing worse than working with sheet goods is working with sheet goods above your head on a ladder. Nevertheless, I would sleep better knowing it was panels of OSB rubbing up against 2 feet of blown-in cellulose insulation rather than sheets of flimsy plastic. Long term solutions do wonders for peace of mind.

first chute installed and sealed

First insulation chute installed.

I used small, cut pieces of 2×4 (6 per OSB sheet) as a screwing base (visible in the photo below) to install each insulation chute  — screwing the blocks first to the roof trusses, then after putting the OSB into place, screwing through the OSB and into the bottom of each 2×4.

close up looking down chute before sealing

The blocks were first screwed to the trusses, before each sheet of OSB was attached to the 2×4 blocks from below.

Then, after installing each sheet of OSB, I went around the perimeter sealing all the gaps. Here’s the product I used for that:

close up Quad Max product label

The OSI sealant I used to cover the gaps.

Here’s what the chutes looked like once they were installed on the south side of the house:

insulation chutes long view

And this is what the chutes looked like when completed at the top of the Zip sheathing:

sealed top of wall w: sealed insulation chute

There weren’t always sizable gaps where the OSB chute met the top of the Zip, but when there was, this was pretty typical:

unsealed warped chute before sealing w: small piece

Same area after adding a thin piece of OSB to help cover the gap, and then sealing the area with the OSI sealant:

sealed small piece at bottom of chute

Looking down a chute before sealing with the OSI:

close up looking down chute before sealing

Gaps visible at the edges before sealing them up with the OSI.

Same view after sealing up the gaps:

close up looking down sealed chute

I showed up on a rainy morning to continue installing the chutes, and this picture shows the dramatic before and after view of without chutes and with chutes installed and sealed:

blue glow before and after chutes

On the left: no chutes and light visible through the soffit. On the right: chutes installed and  completely sealed.

Here’s a long view of the chutes:

epic long view of insulation chutes

49 installed with one to go (far left corner).

 

insulation chutes in corner

Final chute installed and sealed.

 

insulation chutes from outside

View from outside showing the ends of some of the OSB chutes peeking over the edge of the soffit.

 

close up of OSB insulation chutes from outside

Closer view of the top of the Zip sheathing meeting the OSB chute.

 

Intello from attic w: insulation chutes in bg

In the attic with the insulation chutes in the background, after the Intello was installed on the ceiling below.

Once the chutes were installed, I was finally ready to put the Intello on the ceiling, which thankfully I didn’t have to install by myself.

 

Roof Details (Air Sealing #3)

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Top of Wall and Roof Connection

Once the wall assembly details were figured out, and our ceiling set-up detailed, the transition between the two became the next challenge. In other words, how to carry the air barrier over the top of our exterior walls.

I found this helpful article by Chris Corson from The Journal of Light Construction:

An Affordable-Passive-House  (pdf)

Using a waterproof peel-and-stick membrane to wrap over the top of the wall (going from exterior sheathing — in our case 7/16″ Zip sheathing — to interior side of the top plates) seemed like the easiest way to maintain a continuous air barrier at the wall-to-roof junction. The membrane would also have a nice air sealing gasket effect after the trusses were set in place.

I also found this excellent Hammer and Hand video on YouTube (one of their many helpful videos):

Wall-to-Roof Air Barrier

Also, by being able to carry the Zip sheathing up above the top plate of the wall, hugging the bottom of the trusses, meant our 4″ of Roxul Comfortboard 80 over the Zip sheathing would rise above the top of our walls, so that thermally we would be protected going from the exterior walls to the attic, which will be filled with 24″ of blown-in cellulose — making our thermal envelope continuous for the whole house: under the basement slab – exterior of foundation – exterior walls – attic (except for one small gap at the footing-slab-foundation wall connection, which I talk about in a separate post: Foundation Details).

A high R-value wall meets up with a high R-value attic, with no thermal bridging, making our thermal layers continuous. When this is combined with an equally air-tight structure, conditioned air cannot easily escape — resulting in a significantly lower energy demand for heating and cooling (and therefore lower utility bills), and added comfort for the occupants.

Here’s a nice diagram from Fine Homebuilding magazine showing a similar set-up:

021221072-2_med.jpg

Diagram from Fine Homebuilding magazine.

I tried using rolls of conventional peel-and-stick window flashing membrane, purchased from Home Depot and Mendards, but they performed poorly, even in unseasonably warm temperatures for February in Chicago.

I then switched to Grace Ice and Water Shield, normally used as a roofing underlayment along the first 3-6′ of roof edge.

grace-ice-water-shield

Purchased this box at Home Depot.

Since it came on a long roll about 4′ wide, my wife and I cut it down to a series of strips that could more easily be applied to the wall-top plate connection.

While the sun was out, the Grace membrane worked fairly well, especially when pressure was applied with a J-Roller.

grace-vycor-in-the-sun-ii

Grace Ice and Water Shield applied to the top of our wall — covering the Zip sheathing/top plate connection.

Unfortunately, the sun and warmer temperatures didn’t stick around long enough for me to finish.

sealing top of wall w: Grace Vycor in sun

Using a J-Roller to get the Grace Ice and Water Shield to stick better.

 

grace-vycor-in-the-sun

This Simpsons sky didn’t last long. In a matter of hours it was back to rainy, gray, and cold — typical Chicago winter weather for February.

When the weather went gray and cold again, we started to use a heat gun to warm up the Grace membrane, which had turned stiff and nearly useless in the cold.

wagner-heat-gun

Wagner heat gun for warming up the Grace membrane.

After wasting a lot of time and effort trying to pre-heat the Grace membrane before installing it, I finally relented and switched to the much more expensive (but also much more effective) Extoseal Encors tape from Pro Clima. Where the Grace membrane lost virtually all of its stickiness, the Extoseal Encors stuck easily and consistently, with the J-Roller just helping it to lay flatter and more securely.

extoseal-encors-as-gasket

Pro Clima’s Extoseal Encors available from 475 HPBS.

It was a case of trying to be penny wise but ending up pound foolish. Looking back, I would gladly pay an extra $300 in materials to have those hours of frustration back (including the time it took to run to the store and buy the heat gun, which turned out to be ineffective anyway).

installing Extoseal Encors on top of wall cloudy

Finishing up the top of the wall.

After finishing sealing the Zip sheathing-top plate connection on all the outside perimeter walls over the weekend, it was time for the trusses to be installed.

 

 

Trusses

first-truss-swinging-into-place

First truss swinging into place.

Zach let me stand by the front door rough opening and give the crane operator hand signals. It was a fun way to watch the roof take shape.

trusses-going-in-from-inside

Sammy, Zach, and Billy (out of view to the right), landing and setting the trusses.

Once the trusses neared the front door, Zach could signal the crane operator himself, so I was able to get some shots from just outside the construction fence.

 

starting-garage-trusses

Sammy, Zach, and Billy landing trusses on the garage.

 

long-view-of-crane-and-house-east-side

Setting the trusses on the garage — the basic profile of the house comes to life.

Once the trusses were on, and the guys had a chance to install the final top row of Zip sheathing (up to the bottom of the trusses on the exterior side of the wall), I could move inside to seal all the connections from the interior.

 

 

Top of Wall (Interior)

Because of the cold, the Grace membrane was beginning to lift at the edges in certain spots, so just to make sure it had a nice long-term seal, I went around the perimeter of the house and used a layer of Tescon Vana (3″ wide) tape to seal the edge of the Grace membrane.

sealed top plate from interior

Trusses sitting on Grace and Extoseal Encors (other sections of top plate), with the final row of Zip sheathing sealed to the trusses with HF Sealant.

The picture below shows all the connections involved: top of Zip sheathing meeting the roof trusses and the top plate of the outside wall:

sealed top of wall from inside

HF Sealant helps to air seal the Zip-truss and Zip-Grace/Extoseal Encors connections.

 

view of top row of Zip sheathing 1

Looking up at the top row of Zip sheathing attached to the outside edge of the raised heel trusses.

 

 

 

Shingles

We had to wait for shingles for quite some time. First we had to fire our GC’s, and then I had to find a roofer and a plumber (to make penetrations through the roof before the shingles went on). But before the plumber could even start, I had to get the Intello installed on the ceiling. And even before that, I had to figure out the insulation baffles, which I’ll talk about in a separate post.

It took awhile to find a roofer since they would have to make three separate trips for a relatively small job. The first trip was just to set down the Grace Ice and Water Shield at the edges of the roof, along with a synthetic roof underlayment (the consensus was that typical roofing felt wouldn’t hold up to long term exposure). As it turned out, it took weeks before the plumbers made their penetrations through the roof sheathing (literally the day the roofers showed up — a long, horrible story in and of itself that I’ll save for later).

synthetic underlayment at roof peak

Synthetic underlayment covering the ridge line until the shingles and a ridge vent can be installed.

The second trip out was to install the shingles on the roof of the house, while the third trip to install shingles on the garage roof could only happen after the Roxul on the exterior of our Zip sheathing was installed (in order to make a proper sealed connection between the wall of the house and the garage roof).

There weren’t many roofers willing to work with our unique Passive House sequencing, but Peterson Roofing was kind enough to take it on.

Grace ice and water shield rolling up after wind

Grace Ice and Water Shield rolling up on itself after the wind got ahold of it.

Unfortunately, the day after the guys installed the Grace membrane and the synthetic underlayment, we had a cold, blustery day. Once the wind grabbed the Grace membrane, the membrane rolled up on itself, turning it into a real mess.

Because of our recent past bad experiences with general contractors, I just assumed I was on my own, so I spent a couple of hours putting down new layers of the Grace membrane. When Peterson roofing found out, they were shocked I did it myself, and assured me I could’ve called them and they would’ve come back out. We were so used to people not following through, that low expectations meant it didn’t even occur to me to call them.

We initially were going to use Certainteed’s Landmark TL shingle, which mimics a cedar shake shingle profile, but Armando from Midwest Roofing Supply in Schaumburg, Illinois was kind enough to take the time to walk me through the options available, and explained that because our roofline isn’t steep, only the neighbors from their second story windows would get to appreciate the effect. He recommended we save some money, while not giving up on quality or durability, and go with the Landmark Pro product.

shingles being installed w: vents

Shingles going down on the roof of the house.

The shingles went on quickly since we have a relatively small and simple roof. In addition to the aesthetic leap the shingles made on the appearance of the structure, it also meant I didn’t have to go around cleaning up the subfloor every time it rained.

Although the synthetic underlayment worked pretty well at keeping the rain out, if there was significant wind combined with rain, the water easily found its way under the underlayment where it could then drip and fall on the subflooring below — pretty depressing showing up to the job site after a hard rain knowing I was going to spend the first hour just cleaning up and looking for leaks.

roofers shingling south side

Seeing this felt like a tremendous amount of progress was being made. It also meant an end to our roof leaks on the interior.

 

shingle installation progressing

Shingles going on quickly.

After they cut the opening for the ridge vent, but before it was installed, I managed to get this shot from inside:

attic just before ridge vent installed

Attic as cathedral.