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2 Answers

Need help with our ductwork decision

I contacted a reputable contractor to come do a duct test and take a look at our attic insulation. The ducts are very leaky and most of them are the old grey kind and some are not in the best shape. One even was missing all the inner plastic and all you could see was the metal ribbing and fiberglass.

Asked By Blake Lasslett | Jul 29 16
2 Answers

Double wall opening detail


I am embarking on my first energy efficient home in Maine for my own residence. Walking away from the Code Built norm finds me scratching my head a bit.

Double walls at 14", 2X6 and inner 2X4. Stem walls and footing with an insulated and thermally broken floating slab system.

Sill pan recommendations for the door breaks where they will contact directly with the concrete stem wall? I will be using an EPDM sill gasket/10 mil poly/tremco sealant sandwich under all the sill plates and I assume under the thresholds of the many doors.

Asked By David Chapman | Jul 29 16
1 Answer

Interior vapor barrier

We had one room remodeled. One west wall (upstairs),one north and south wall now has outside insulation, fiberglass interior, poly sheet vapor barrier, and dry wall. Now I am wondering if we need to remove it. It is only in one bedroom, but I read your article and now I am concerned. Please give your thoughts. Thanks.

Asked By Phette Place | Jul 29 16
1 Answer

Which way should the polyiso foil face when installing over drywall?

I plan to install 1-1/4" polyiso foamboard over existing drywall, then 3/4" furring strips, then 1/2" of drywall. Should the foil face towards the interior or the exterior?

If it matters, this is for Austin, TX 78722 where we need more cooling than heating, and I'll be using two layers of polyiso (1/2" + 3/4"), because I can't find 1" polyiso locally. I do plan to tape the edges to prevent degradation of the foamboard. Thank you for your help.

Asked By Michael Bluejay | Jul 30 16
2 Answers

Insulating stud wall crawlspace with rigid foam

Apologies if this has been answered already, but I haven't been able to find an answer here or elsewhere. There are lots of great articles on rigid foam over concrete, but apparently a stud-wall crawlspace is uncommon--I haven't found any recommendations for that configuration.

Asked By David Bump | Jul 29 16
3 Answers

Help with old building in Michigan

I’m looking for some advice on how to properly sheathe and insulate exterior walls on an old commercial building. The property is in Ludington, Michigan (Zone 6) and right now (from the inside out) there are 1” pine boards, actual 2”x4” studs on 16” centers, no insulation, and old cedar clapboard siding.

Asked By Edgar Struble | Jul 29 16
11 Answers

ERV + dehumidifier ducting in a minisplit house

I'm working on a 2400sf house (CZ4, but very nearly 3) where the owners have selected minisplits - one ductless 1st floor, one ducted w/ very short runs for each of 2nd & 3rd. So there will be no major duct lines throughout the house for heatning and AC. They've also chosen to go the ERV and Dehumidifier route, this being the humid southeast.

Asked By Chris B | Jul 28 16
5 Answers

Separation of concrete slab and foundation

We removed carpeting in a condo that we own. We noticed by the sliding glass doors a crack in the slab. The slab has a layer of rigid insulation on the perimeter which seems to have seperated from the cinder block foundation. The cinder block wall does not appear to be bowing looking at it from the outside. Is this a big concern or is there a way to fix the problem without ripping everything up?

Asked By Joel Silverman | Jul 29 16
4 Answers

Zone 6 Dew point

2"x6" wall
Roxul Comfort Batt R 23 in cavity
OSB Exterior
R-Tech 1/2" R 1.93 foil facer facing OSB, poly facer facing out, tape all seams
Owens Corning Fomular 150 2" R 10

In your opinion is this an acceptable wall structure for Zone 6, or do you need to add an interior or exterior vapor retarder. The R-Tech product has a water vapor transmission <1 (perms) and Absorption <1 (% vol)

Asked By David Dunn | Jul 29 16
14 Answers

Open-cell foam contacting a water heater flue

I have open cell foam being put into my attic. My hot water heater is in the garage below, but where the flue goes through the rafters, is it OK for the open cell foam to contact around the flue? If not, how much of a gap is left around it? I guess they would have to just cut that gap after foaming since the foam isnt going to just cooperate....

Asked By John Sexton | Jul 27 16
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