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18 Answers

Exterior wall "headers"

I'm planning to build a one story 'green' energy efficient, net zero with PV panels, house in northern Michigan. I plan on using 'advanced framing' 24" OC for my exterior double stud walls. I would like to use trusses specifically made to "replace" one stud or two studs (this may require some slight 'repositioning' of openings). The trusses bottom chord would be the top of the rough opening and it's top chord would sit directly under the single top plate. In my situation, only two truss lengths would be needed , 46 1/2" and 70 1/2"..

In Green building techniques | Asked By Jerry Liebler | Jun 12 12
4 Answers

Moisture question with rigid Insulation on interior of poured concrete basement walls.


I know this question may have been beaten to death, but I haven't been able to find this specific details in any of the posts on here yet.

I have a basement with poured concrete walls that have a slight moisture issue (they weep very slightly in spring and fall when it rains excessively). So I know that I'm supposed to insulate them using EPS, PolyISO or closed-cell spray polyurethane foam and then build my walls on top of the insulation. I also understand that I should NOT use any vapor barrier so that the moisture doesn't get locked in.

In Green building techniques | Asked By George Heinrich | Jun 18 12
49 Answers

Airtight Drywall... Anyone?

There are a handful of people here at GBA talking about Airtight Drywall.

Have you tried it?
Would you do it again?

I am trying to figure out why there is not much discussion about it?

I will post a link to Martin Holladay's FHB article and a Link to the BSC instructions.

Does anyone have other links to Airtight Drywall Details?

In Energy efficiency and durability | Asked By John Brooks | Feb 7 11
8 Answers

I need a photo of stack effect

I am putting together an article on air barriers with John Straube for an upcoming Fine Homebuilding article and would like to use a skyscraper wrapped in fabric bubbling at the top and sucking in at the bottom as the lead image.

You all know the photo, we've all seen them.

Now that I need one, I am having trouble locating one. Do any of you have a high resolution image like that that I could use? Alternatively do any of you know of a high rise goiing up somewhere near new England that I could drive to for a few photos?

Thanks in advance,

In General questions | Asked By Daniel Morrison | Jun 15 12
0 Answers

Insulating/Designing Walkable Flat Roof Deck over Conditioned Space


I would appreciate your advice on a renovation to a 70 year old post war gable roofed 1 1/2 story in a Zone 6 cold climate high snow load climate (Rossland BC Canada) annual snowfall 145 inches. I am confused particularly on the feasibility of an unvented roof in this climate and how to convince my inspector that it is possible.

In GBA Pro help | Asked By Derek Lum | Jun 18 12
4 Answers

Outsulation-to-insulation ratio?

I have 2 inches of foil-faced polyiso over Typar on the exterior of my north wall. It is strapped with vinyl over the strapping.

How much interior insulation can I have on this wall, and do I need an air barrier? Reason I ask about the air barrier is because some of the gable wall space is behind the kneewall where I really don't feel like hanging sheetrock or paper unless I really have to...

Also, can I use XPS on the interior or will this create a double vapor barrier? I'm in zone 6.

In General questions | Asked By stephen edge | Jun 17 12
0 Answers

Looking for south Jersey green builder

Building a double-wall superinsulated 2-story home. Looking for a builder with experience (or excited to learn).

In General questions | Asked By Michael Arnold | Jun 17 12
3 Answers

Gasket thickness for airtight drywall

We are planning to install Denarco Sure-Seal gaskets for airtight drywall. Wondering what would be a thick enough gasket, that wouldn't cause problems when installing the 4/4 (3/4") thick wood trim?

Would 1/4" thick be enough? From what I have gathered reading online, 3/8" x 3/8" is usually used. Have there been any tests done to determine the best thickness?

Thank you in advance.

In Energy efficiency and durability | Asked By Ken Morton | Jun 15 12
4 Answers

Plywood sheathing thickness

For a single floor residence Is nominal 3/8 plywood acceptable sheathing on 10 foot tall walls built with 24" OC advanced framing?

In Building Code Questions | Asked By Jerry Liebler | Jun 6 12
2 Answers

XPS on both sides of foundation wall

I have 2 inches of XPS on the outside of my basement walls, both above and below grade. I was considering putting 2 inches on the inside as well, followed by a framed wall with R-23 Roxul and sheetrock.

Are there any risks with this assembly?

In General questions | Asked By stephen edge | Jun 14 12
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