Gaskets and Air Tightness without Sprayfoam

[John B]

I think that we should be focusing more on airtightness.
We should think beyond 3 ACH50
I have had good results (1.4 ACH50) with a combination of spray foam in the cavities and conventional "sealing" at framing/framing and framing /concrete.
I would like to go beyond 1.4 ACH50 and I would like to avoid sprayfoam.

Recent JLC Articles by Dan Kolbert and Thorsten Chlupp offer examples of excellent airtightness without sprayfoam.

Is anyone else achieving Better than 1.5ACH50 without sprayfoam?
If So How?

I would also like to collect sources for Gasket Products and talk about installation issues.
Anyone with Gasket knowledge or suggestions for products or installation please post here.

[Allan Edwards]

Re: Gaskets and Air Tightness without Sprayfoam

Can someone tell me where gaskets are used other than under bottom plates?

[Dancing Dan]

Re: Gaskets and Air Tightness without Sprayfoam

I like Resource Conservation's gaskets quite a bit. We use them instead of sill seal, and I think on our next house we're going to get the 1-1/2" stuff and attach it to the outside edge of the mudsill - it was a weak area in our assembly last time.

[greentree]

Re: Gaskets and Air Tightness without Sprayfoam

Can someone tell me where gaskets are used other than under bottom plates?

I've never seen this done, but it wouldn't take much to gasket the perimieter of a wall laying on the deck and at sheet joints before sheathing for those that build and sheet walls on the deck.

I realize this is still using foam, but would it pay to take a foam gun and run it around each wall cavity then do a cellulose dense pack to get a seal and decent r-value?

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Greentree ...
I do not think that we really need to seal the perimeter of every cavity.
Concerning Drywall .... the tape and mud will take care of the drywall to drywall joints.
The places that need special attention are the places where the drywall "stops"
...at every opening for windows,doors,vents,wires,outlet boxes,switch boxes,plumbing...etc.
AND at the bottom edge of the Drywall.
If we could isolate the interior partition walls and cavities from the exterior walls....
Then we could limit all of that fussy stuff to the exterior walls.

Same goes for an exterior Air Barrier Like ZIP or similar ..the special attention is where the sheathing "stops"...... at every opening and at the top and bottom of the sheathing plane.

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Beacuse of all the "fussy issues" mentioned above....I am considering avoiding wiring and plumbing completly in the exterior wall....and add an architectural "wainscot" interior of the drywall air barrier.....The Euros call it a service core.
The service core could vary in height like wainscot and sometimes be full height...as needed or desired.
It would be possible to add more cavity insulation to the service core...and thermally isolate the bottom plate thermal bridge.

[billnunez]

Re: Gaskets and Air Tightness without Sprayfoam

Beacuse of all the "fussy issues" mentioned above....I am considering avoiding wiring and plumbing completly in the exterior wall....and add an architectural "wainscot" interior of the drywall air barrier.....The Euros call it a service core.
The service core could vary in height like wainscot and sometimes be full height...as needed or desired.
It would be possible to add more cavity insulation to the service core...and thermally isolate the bottom plate thermal bridge.

As a remodeler, I've often longed for something akin to the "service core" idea merely for the functionality. When I was a college kid I worked for an industrial electrician at a Hitachi plant, and we had all kinds of cool ways to run wire...under raised floors, in ceiling trays etc. When I got into residential work, I was shocked at what a hassle it can be to make changes. I'm all for shifting our focus to more function oriented.

To boot, I think you're onto something as far as having an unbroken exterior envelope. Also, you could get your exterior walls done w/o waiting on the damn electricians to finish rough-in!

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Bill,
Something I remember from a discussion about European walls was the comment that the service core protected the air barrier from the occupants...

Here's another "oddity" about some Euro-walls......
They do not always break their sheet-goods on the studs.
This allows the panel joints for the exterior sheathing to be taped with air-stop tape from the inside as well as the outside.

[Dick Seibert]

Re: Gaskets and Air Tightness without Sprayfoam

I don't get it, as I've quoted Joe Lstiburek before: "I've said it before and I'll say it again, stucco doesn't leak air, period". After all the air-sealing comments here I went to see my Title 24 consultant, I asked him if he put taped Tyvek on a building rather than asphalt felt or two-layer Kraft paper would it make a difference in his program's calculations, he said: "Our homes don't leak air, it wouldn't make a bit of difference."

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Dick,
Ask your consultant what kind of blower door results they are getting.
He should be able to give you an answer in units of ACH at 50pascals
"Don't leak air" is not really a unit of measurement.

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Dick,
I hope you have noticed that I am looking to avoid spray foam....
And I think that high performance glass is very important.... ;-)
I am looking for ways to avoid all foam products.

[Dancing Dan]

Re: Gaskets and Air Tightness without Sprayfoam

You're not using DLA's in your buildings? In Maine we call them "Siebert Units," and you can have either a 1 or a 0.

[Dick Seibert]

Re: Gaskets and Air Tightness without Sprayfoam

John:

I did notice, wise move, for my part I'm planning to come out of retirement and build a 5,000 square foot home that will use virtually no energy, no solar panels though, the owner is a Silicon Valley guy who is up on this stuff and wants to wait until the technology catches up with transistorized light capture.

Nobody has done blower door tests around here in the past. Now several of the con-men selling energy efficiency have bought them, and our county has bought them in it's program to do free stimulus money retrofits.

An ex-employee worked briefly for one of the con-men, he told me that before they did their work the bulk of the air leakage was through the windows and the HVAC ducts, after they sealed the ducts and replaced the windows most of it was through the new windows. I asked him to bring it by and try it on my house, unfortunately he quit on my advice before he brought it by, I wish I hadn't made such a point of telling him about being involved in fraud, at least until he did my home or one of my customers' homes.

I will give the Title 24 consultant a call, at the time I visited he was waiting for those in his industry to decide what they were going to do about the new ASHRAE 62.2 requirement mandating fans, he thought that this was going to considerably increase energy consumption to run the fans and condition the exterior air being pumped in, I have an E-mail into Building Standards to see whether the Energy Standards actually became mandatory on August 1st, they haven't responded yet but he may know, I'll try calling him tomorrow.

Dan:

I guess I've become the prodigal son in Maine, maybe they'll slay the fatted calf for me (see Johnson, I know your stuff, some of it anyway). .

[Bluewoodrock]

Re: Gaskets and Air Tightness without Sprayfoam

I don't get it, as I've quoted Joe Lstiburek before: "I've said it before and I'll say it again, stucco doesn't leak air, period."

Since you like to bring up this quote so much, in the interest of full disclosure, the rest of the quote from Dr. Joe is:

" there are 2 kinds of stucco. The kind that's cracked, and the kind that isn't cracked..... yet"

[John B]

Re: Gaskets and Air Tightness without Sprayfoam

Dick,
If con-men have used blower doors to dupe consumers...It does not follow that blower door testing is a fraud.
Your logic is twisted.
If you do not understand the significance of airtightness on energy performance AND DURABILTY...then you are living in the dark ages.
I urge you to study this more before you come out of retirement.