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!

5 Answers

Best HVAC options for large house in zone 5a.

I have a custom house with 3930 sq/ft of conditioned space in a development in northern Idaho, (Zone 5a). The basement is planned to be Logix Platinum ICFs with R-28, the main and upper floors planned as 2x6 advanced framing walls with cellulose, 7/16" OSB, Tamlyn Drainable Housewrap, 1.5" of Terrafoam EPS, and fiber cement siding.
I'm hoping to get the owner to agree to spray foam the attic sheeting to condition it (R-38 min.)
The basement is 1830 sq/ft including a conditioned space under a large garage. The upper two floors of living space are 1050 sq/ft each.

Asked By Nethaniel Ealy | Apr 15 15
3 Answers

Various spray foam companies


Would like to know if there any significant differences between the spray foam made by various companies?
We have two vendors in our area and one uses Bayer for Open cell and Dow for Closed cell, while the other vendor uses, Premium and Johns Manville?

Help greatly appreciated


Asked By Yasir Khan | Apr 15 15
1 Answer

How should I insulate cavities underneath a subfloor?

Part of our dining room is built over a small area that consists of 2x12 joists that sit directly on concrete. The reason this small area was built this way was because it was an extension to an old foundation.
What is the best way to insulate the space between the joists (i.e., the cavities)? This area becomes quite cold because it is on the outside edge of the house. My concern is that moisture will build up under the subfloor.

Asked By Shlomo drexler | Apr 15 15
1 Answer

New Home - Wall Assembly Review

I'm building my first custom home this summer and could use GBA's collective wisdom to vet the wall assemblies.

Zone 5a
Logix Platinum ICF basement (R-28)
2x6 advanced framing, blown cellulose, 7/16" OSB, Tamlyn Drainable WRB, 1.5" Terrafoan EPS, Fiber cement or steel siding.
Conditioned attic with min. R-38 closed cell spray foam
"Innie" window placement

Will placing the drainable WRB between the sheeting and EPS cause air flow that will serve to defeat the EPS insulation?
Does this mean I should move to an "Outie" window placement?

Asked By Nethaniel Ealy | Apr 16 15
22 Answers

Can a house be built without wood?

A thought experiment, no wood beams, studs, sheathing, subfloor, rafters or anything else that is part of the house (wood furniture or other possessions are fine, we are far from a paperless society). With a price comparable or at most 50% more then a conventional house how would one build a house with a basement, main floor, second floor if possible, attic and roof?

Of course it should be insulated, the 5/10/20/40/60 would be fine, and would have the usual amenities, washer/dryer, fridge/stove, pluming, electricity etc.

Asked By Alan B | Apr 11 15
5 Answers

Multisplit temperature control per zone

I am considering a multisplit heatpump system for our 3000 s.f. two-story renovation located in Chicago, Zone 5. I like the idea of a multisplit system for its high efficiency and zone control. I would like to provide 1 unit per bedroom using ducted interior units that supply conditioned air to each bedroom.

Asked By AlokKhuntia | Apr 14 15
4 Answers

WRB advice

Finishing several additions to a coastal home in South Georgia.
Basically...plywood, wrb, vented furring strips, cedar shingle sidewall.
Due to the hot summer we plan to go north for 4 months and won't be able to completely finish the exterior. Looks like the WRB applied is about as far as I can get.. So...what wrb to use.
I know these products have limited "uncover" time.
Thinking a liquid applied WRB might be the way to go...considering wind, ripping, etc.
Any thoughts......thanks

Asked By Robert Brown | Apr 15 15
4 Answers

Warren Thatcher "Build a container home" guide worthwhile?

I can find no decent review of this guy's downloadable content, though his marketing scheme is amazing. Does anyone have any first hand information about the contents of his guide?

Asked By Hal Ferguson | Apr 14 15
6 Answers

Can anyone direct me to the best information on wiring a new residence for 100% LED lighting?

I am looking for LED wiring 101 ~ What are wire gauge options, voltage regulating options and what are the things to watch out for?

I understand we are still very much in a hybrid AC/DC universe and AC has to exist for kitchen appliances, and infrastructure appliances in the Utility room, however our client wants to take the step into LED. The house is around 1600sf and one floor.

Asked By Caroline Di Diego | Apr 13 15
6 Answers

Can I insulate between brick veneer siding and the wall studs?

I have a home built in 1977 and my south wall is cold in the winter. Can I safely inject foam insulation in the air gap behind the brick veneer. The company that does this work told me it was okay to do this; however, no one I have asked that laid the bricks or sold the bricks thinks it is a good idea. They tell me that this area is needed to get rid of any moisture that might happen between the brick and the gypsum board backing. I have been told I need this space for moisture to evaporate. . I do have fiberglass insulation but this wall is still cold.

Asked By Seeger | Apr 11 15
Register for a free account and join the conversation

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