Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!

3 Answers

I just purchased a new spec house and I'm going to install an HRV to improve the indoor air quality. The house is at the very bottom edge of climate zone 5a.

Would be okay to install the HRV in the garage? The AHU and furnace are in the garage along with the water heater, so this would be the easiest place to install the HRV. The installation manual for the Fantech HRV I am considering says it should be installed in a "heated" space but it doesn't specify a temperature.

In General questions | Asked By Patrick Cantwell | Jul 17 14
3 Answers

We recently had blown in insulation installed in the attic of our Cape Cod style house up to an R-49.
But we do have some gaps that couldn't be addressed by the blown-in insulation and those are still to be tackled. The picture below was taken prior to the blown in insulation. June was the first full month with the added insulation but we saw no drop in electrical usage from the June 2013. I know there are a lot of variables, but would the insulation gaps in the stairwell and left side kneewalls (to a lesser extent) negate all the added insulation?

In General questions | Asked By HD S | Jul 14 14
1 Answer

I am a homeowner, little sun from Nov to March, average daytime winter temp -8 C, night -15 C, with intermittent -20 C days lasting no more than a week, summer daytime temp, average mid 30 C, night 20 C, with intermittent weeks of high 30 C., average annual rainfall 20 inches, average annual snowfall 60 inches, generally calm, however, can get an occasional rare storm with winds of 20-40 mph and generally low humidity particularly in the winter.

In GBA Pro help | Asked By Marilyn Limbert | Jul 16 14
10 Answers

I am interested in converting our bungalow attic to finished space, and it was not designed for venting. I've heard I can do a hot roof insulation method using spray foam. However, I am a DIY guy by nature, and was interested in methods I've seen using closed-cell polyiso rigid foam and spray foam cans to achieve the same result, at least in walls. I am curious about using this method on a hot roof. Surely it would cause head-scratching with code officers. Would it work, though?

In Energy efficiency and durability | Asked By Asa Bradford | Jul 13 14
3 Answers

I was pretty much on board with buying Raycore for the 4500 s.f. home I am building in downstate NY, which is steel framed, so I actually don't need any structural value out of the exterior walls other than for supporting the windows and doors (and supporting the walls themselves). I am also going with a wire lathe and stucco on the exterior - Raycore told me I could direct apply the wire lathe and did not have to use any sheathing if I did not need the shear strength, but I am hesitant to do so.

In Green products and materials | Asked By Joe McCarthy | Jul 14 14
27 Answers

I thought I was on the right track but I am not so sure now ...42000 btu is the heat loss number .It is a 1200 sq ft slab on grade 1.5 storey .Total living space is 1900 sq. feet .It is 2by 6 blown in fiberglass with 2.5 inches of EPS on the exterior .We do have lots of triple pane large high windows on the lake side which is a north east exposure ...,that one large combo living,kitchen,dining room is a 17000 btu heat load .I was hoping to heat it with a Fujitsu mini split on each level ...Is that still a viable option ? I am in Peterborough Ontario which is a zone 6 ...thanks,Bob

In General questions | Asked By bob holodinsky | Jul 8 14
1 Answer

The cathedral ceiling roof assembly on a recent addition to my house consists of vented fiberglass-filled bays with with an interior layer of 1/2" foil-faced polyiso under the 2x10 rafters.

Investigating a strong odor on hot days, I found that the builder...

Michael Roland,
Nassau, NY

In Green building techniques | Asked By Michael Roland | Jul 16 14
3 Answers

Isn't there an intrinsic problem with SCIP (structural concrete insulated panels) that the reinforcing trusses bridge the insulation.

In General questions | Asked By Stephan Green | Jul 14 14
1 Answer

Hi,
I’d like your recommendation on sealing rafter bays of a currently vented cathedral ceiling.

I’m doing a remodel of a small room (20 X 20 feet); the roof/ ceiling were built as a vented roof assembly complete with a ridge and soffit vents.

In General questions | Asked By Anthony Jackson | Jul 15 14
3 Answers

My proposed wall assembly from outside to inside:

1. Ribbed steel siding
2. 3/6" fanfold battens to create air space
3. 1/2" cdx
4. 2x8 stud cavity filled with wet spray cellulose
5. 2" eps nailed to studs (interior uninterrupted rigid foam)
6. 1.5" uninsulated service cavity (created with horizontal 2x4s)
7. 3/8" acx plywood (interior wall finish)

The building is a heated workshop with some pretty high electrical needs for the machinery. Since it's not a residence, I could probably forgo the fire blocking.

In Building Code Questions | Asked By Rick Van Handel | Jul 14 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!