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38 Answers

AECB Website and Point Thermal Bridges

Some interesting thoughts about thermal bridges in this document.....

"Point thermal bridges -.....the nails, screws and other fixings in timber-frame construction."

My Question is Concerning Outsulation Strategies.....
What is the thermal effect of the 100's of large "nails,screws and other fixings" that penetrate the outsulation and terminate in the studs and plates( which are also thermal bridges)?
In other words...a thermal bridge connected to a thermal bridge.
Is it significant?

In Green building techniques | Asked By John Brooks | Oct 12 09
4 Answers

Half wall basement ?

I priced spray foam and it was 3k so we want to use xps on the block walls and in the rim joist area. Since the 2x4 walls are only 1/2" from the block wall I can't fit any foam back there can I cut the foam to fit between the studs and fill the area behind the stud with canned foam?
Do I caulk the sill area or foam it?
The area above the block wall is the above grade wall and it has fiberglass batts and is 2"x6" framing then the 2"x4" frame is in front of that to make a flat wall to the ceiling how should this upper wall be insulate? XPS? Fiberglass a combo and how much R-value?

In GBA Pro help | Asked By Kelli Cornwell | Nov 11 12
3 Answers

Does a vapor barrier belong above my steel ceiling in heated shop?

Having been nicely schooled on reasons not to put vapor barrier on my walls with exterior foam in zone 6, SE MN, I now wonder about the proper way to insulate the ceiling. This is a heated shop with a vented roof and scissors trusses. I would like to use ribbed steel panels for the ceiling, and have been given rolls of R38 unfaced insulation that I would place on top of the steel panels.

In General questions | Asked By Kent Jeffery | Nov 12 12
4 Answers

New sheathing or not?

I have a 1950's era ranch house that is in Delaware (zone 4). I am starting a renovation where I have to replace the roofing, siding, windows and doors.

The sheathing on the house is 1x6 t&g boards that have large gaps between them. I also do not have any insulation in the walls. I should also add that my inside walls are not conventional drywall or plaster lathe. It is some type of 16" wide strips of 1/2" drywall-like material that is covered with another 1/2" of mortar. It is strange (and hard as concrete) but I have seen it in a few houses in my area.

In Energy efficiency and durability | Asked By Joe LeBright | Nov 10 12
7 Answers

Spray foam sealed attic 1.5 story house question

My wife and I are planning to build a 1.5 story home. By this I mean that we will have a game room, office, and a planned future moive room upstairs in the "attic" space. The office will protrude out of the 1 story roofline as a former, but other than that, everything is contained within the 1 story 8/12 roofline. The rooms are centered and sized such that there are no hip walls, and all have an 8 ft beam.

In Plans Review | Asked By Dustin Gohmert | Nov 10 12
1 Answer

Alternate compliance to the IRC thermal barrier requirement for foam insulation

I am planning on doing unfaced fiberglass batt insulation over spray foam plus continuous polyiso on the exterior of a small new house. The building code (R316.4) requires thermal barriers between the interior useable space and foam insulation and the prescribed way of meeting that is 1/2" gyp board. I was hoping to do wood interior walls and ceilings - plank, OSB or even metal and not do any gyp board.

In Building Code Questions | Asked By Timothy Gooding | Nov 9 12
14 Answers

Is there an alternative to the under-slab rigid insulation system in passive house design?

I think I saw a detail somewhere showing an insulated suspended floor over a crawl space in lieu of the slab on rigid normally used.

In Green building techniques | Asked By Janet Digby | Nov 2 12
3 Answers

GU24 base CFL?

I have just had a home built that is an energy efficient home. All the light fixtures are designed to take gu24 CFL's. After three days the first CFL blew the second within a week the third just blew and we have not been in the home a month. I had a electrician check the voltage and earth to the CFL ha says there is no problem with the wiring.

In Green products and materials | Asked By Rev.Alan Perry | Nov 2 12
7 Answers

Is my slab at risk left unheated through the winter?

I had grand plans for getting my garage closed in, and the rough mechanicals installed before winter. Life (uh... work, actually...) intervened.

I live in MN zone 6, and am building on alluvial sand from the Mississippi River. I built a block stem well on poured footings four feet deep (below frost line), 12 inches of compacted sand was placed on top of undisturbed sandy soil.

In General questions | Asked By Kent Jeffery | Nov 7 12
10 Answers

Condensation on Windows in a 105 Degree Heated Room

Hoping some building science folks might have some good suggestions. I'm helping a contractor friend build out a yoga studio in a commercial space. The yoga that's going to be practiced there is hot yoga, more specifically Bikram which calls for a room temperature of 105 degrees (yes, you read that correctly. I actually practice Bikram and it's pretty great).

In Energy efficiency and durability | Asked By Chris Ermides | Nov 7 12
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