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!

1 Answer

We're building a pretty good green home in Gardnerville, NV, a place that gets 8" rain per year. We get cold in the winter (-10°) and are pretty warm in summer, about 10 days with >100° temps. Radon is an issue in our area. Our new home is being constructed with SIPs, therefore no attic space. We have natural gas at the site, pretty cheap in Northern NV. Our plan is forced air heating via Natural Gas in winter and a few days in summer when we'll use A/C.

Asked By Richard Starrett | Apr 18 14
6 Answers

In building a home in zone 4 (western NC), I am interested in determining the better way to go to create an effective air barrier:

Outside in:

Option 1: Hardie, 1 x 4 Furring for 3/4" Rainscreen Gap, 2" Roxul ComfortBoard IS, #30 Felt, 1/2" MgO Sheathing, 2 x 6 Stud Wall with 5 1/2" of Roxul ComfortBatt in the Cavities, 1/2" Mgo Wall Board using the Airtight Drywall Approach

Asked By Stacey Owens | Apr 17 14
32 Answers

In another thread, my choice for HVAC was appropriately questioned. The system seems inordinately complex, costly, and convoluted. At least, on the surface. But digging deeper, the reasoning behind the design becomes clear. But, does that make it right? Is this the best HVAC design, or is it redundant and wasteful?

Here are the pertinents:
• Climate Zone 6
• 2700 sq. ft. finished space in story-and-a-half (bungalow style) house
• 2000 sq. ft. unfinished basement (future completion for aging parents)
• 4 Bdrm, 3 ½ bath house
• Tight, highly insulated home

Asked By Kent Jeffery | Apr 16 14
4 Answers

I have a 1971Lancer double wide mobile home with hardboard exterior walls that seem to be toxic. I am sensitized to chemicals due to chronic pain and fatigue. The hardboard has a strong petrochemical aroma when the sun heats it; or when i open up the wall space, such as when working on an 120v wall box. I have been around all the other house components before (vinyl, paint, carpeting, MDF, etc) and have finally realized its the hardboard that is the main culprit.

Asked By Joe Tichenor | Apr 18 14
6 Answers

We are finishing a space above our garage, about 26 x 26', to make a studio, and are trying to keep costs down and still insulate it well. Is the difference in price between the two types justified in improved insulating quality over time or is the actual insulation pretty comparable? The cellulose people are adamant about their product, and the fiberglass people say the difference is negligible. And then how much more/less green are the two? Thank you!

Asked By Patricia Basha | Apr 17 14
1 Answer

I have a radiant floor that was installed under my kitchen floor using the aluminium heat transfer plates. Below the kitchen is a semi finished, semi conditioned basement. I would like to insulate the floor to allow as much of the heat from the pex tubing to translate to the floor (rather than helping heat the basement). Is a radiant barrier (foil) with an airspace beneficial? does the insulation need to be installed airtight? Is fiberglass a good choice in this application? Any insight is appreciated!

Asked By Pete Marthaler - Zone 7 | Apr 18 14
2 Answers

In an answer to a recent question I had, Martin Holladay indicated that he has concerns about AirKrete shrinking and crumbling. According to the website and company representatives, AirKrete has 0% shrinkage and the formulation has been changed to alleviate the friability concerns.

I'm interested to know if anyone here has used AirKrete and, if so, what your experiences are with it.

Thanks in advance!

Asked By Stacey Owens | Apr 15 14
1 Answer

I have a recurring question / situation that comes up in my east central MN location (6b-7a border). There are many 1970's homes undergoing remodeling and looking to add insulation for improved comfort and energy effciency. Miost common construction is drywall, kraft faced R13, 2x4 walls, 3/4" Bildrite (asphalt fiberboard sheathing).

Asked By Troy Tvedt | Apr 17 14
3 Answers

Hey guys, what are your experiences with putting a 100 psi polystyrene under a footing to help eliminate as much thermal bridging as possible? This is for a residential setting. It would be in the center of the house the load of the first and second floor and possibly the roof would be on it.
Can anyone recommend a engineer that may have experience in this?
Thanks.

Asked By Kirk Nygren | Apr 16 14
11 Answers

So, I’ve been researching the proverbial pee-pee out of this question: dedicated ductwork for my HRV or simplified installation? Here are the pertinents:
• Climate Zone 6
• 2700 sq. ft. story-and-a-half house, along with a 2000 sq. ft. unfinished basement
• 4 Bdrm, 3 ½ bath house
• Double stud walls, spray foamed exterior sheathing and cathedral ceiling, very “tight” and efficient house planned.
• Geothermal ground source heat pump, with gas furnace back-up (Xcel Energy “dual fuel” program allowing electricity to be purchased at 40% rate for geo.)

Asked By Kent Jeffery | Apr 15 14
Register for a free account and join the conversation


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