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3 Answers

Am I OK to lay down my plywood subfloor at 19% moisture content?


I tested all of my 4x8 cdx plywood in the middle of the 5 sheets, and 2 pieces are at 19% moisture content (the rest are between 10-17%).

Should I go buy 2 new pieces or am I too concerned over the moisture content? I was reading that anything near the 20% range is way too high for plywood.

I purchased these 3 weeks ago and have been stacked in my shed. I did not test when I first purchased but I certainly would assume that they would be dryer.

Also, please see the pictures below. Does this look like water damage or mold? These are the two pieces that measured higher.

Asked By Grey Wolf | Apr 27 17
10 Answers

Cape Cod attic — cellulose machine

My finished attic in my cape cod has terrible temperature regulation up here in central Maine. So far I've put 1 inch foam between the floor joists sealed the gap with foam. I've also spent days air ceiling the upper attic. Next step is for me to dense pack the sloped ceiling, which is made up of 2x8 rafters. I'll be using accuvent cathedral ceiling extensions to provide ventilation. The sloped ceiling is about 5.5 feet long so I'll be connecting two of the vents together and stapling at either side. The house is about 34 feet long and I have slopes on either side.

Asked By SciFiJock | Apr 25 17
3 Answers

Venting a roof framed over a roof

I have a ventilation question I have just thought of while designing a home. The house is a 1.5 story home (framed as a cape style but turned 90 degrees so the front entrance is the gable wall).

Asked By User-6801629 | Apr 27 17
4 Answers

Advice to GBA readers with goofy screen names

Because of a web site glitch, the GBA site hasn't been displaying the names of recently registered readers properly. Lately, we've been getting screen names like "N/A N/A" and "User-85612."

Some new readers have chosen aliases like YellowFrog or RedSoxFan.

GBA encourages the use of real names. If you have been assigned a goofy screen name like N/A N/A, or if you are willing to change your screen name from YellowFrog to your real first and last names, there's a way you can fix the problem.

Asked By Martin Holladay | Apr 28 17
15 Answers

Is a single head minisplit practical?

This is a mostly accurate plan of dear, old Mom's house.
2265 ft²; zone 4 marine; target ACH50 = 1.5; 5000 HDD; 22°F design temp;
2x6 walls w/2 stud corners, 24" o.c., 1½" horizontal cross-hatched walls (similar to "Mooney"), 7" of dense pack cellulose; front wall faces north; awesome PV potential on south facing roof.

Asked By Mark Walker | Apr 27 17
18 Answers

All-electric vs. natural gas in Zone 2

I'm building a house in Houston, Texas. It will probably be a 'pretty good' house - dense pack cellulose and exterior rigid foam installation with an encapsulated attic and targeting an ACH50 of <3 with an ERV system for ventilation. I will have a sizeable solar PV array on the roof - 6-8 kw so I have been debating whether to use natural gas as in my current house for multiple appliances or go all electric. Pros and Cons as I see them are:

Benefits all electric:
No standing monthly charge of $25 for gas since consumption is below threshold 9 months of year

Asked By user-6822325 | Apr 22 17
1 Answer

How Much Foam=A Thermal Break?

I am building in Western NC in Zone 4. In designing my "ideal wall", I would like to include a thermal break. Since code does not require any amount of exterior foam for this Zone, what would constitute "enough"? I plan to use Zip-R sheathing, and would like to keep it as thin as possible despite all of Huber's reassurances on it being an effective structural sheathing, even in the thicker versions. So, would the 1/2" be enough of a thermal break? 1"?

Asked By Kevin Spellman | Apr 28 17
11 Answers

Advice on my wall assembly

Hello, I'm getting ready to build a new home in western North Carolina. I would appreciate advice on my proposed wall assembly. 2x4 walls with huber's R-Zip 9.6 (2" thick overall) and coravent studi battens for a rain screen assembly. The idea is to end up with a wall assembly thickness so I can order windows for a 2x6 wall and have them work. So I end up with drywall(1/2") + 2x4 wall (3 1/2")+ Rzip board (2") + sturdi batten coravent (7/16") = 6 7/16". I was planning on closed cell foam in the 2x4 wall cavity.

Does this seem like a reasonable assembly?

Asked By Jeffrey Higel | Feb 8 17
2 Answers

Is 35 year-old under-attic-floor fiberglass insulation a health issue?

I'm asking about the formaldehyde issue. We'll be spray foaming the attic soon--R38 rafters and R21 gable walls. The contractor would like to remove as much of the under-floor fiberglass as possible to make it a better conditioned space. We're not so inclined, since our attic will really only be for storage, central AC maintenance, etc. and as long as the temps up there don't vary by more than a few degrees, the winter cold or summer heat outside shouldn't affect us in the floors below.

Asked By David Goldman | Apr 28 17
0 Answers

Vented crawlspace - air barrier

I am trying to figure out the construction details for a new home build in Washington state, climate zone 4C (marine). I have been spending many hours trying to educate myself on GBA and with the "Musing of an Energy Nerd" (great book Martin).

Given the unique climate in the Pacific North West, the prevailing design for homes is vented crawlspaces. They appear to work well due to the lack of hot humid air conditions. I also understand that an unvented crawlspace is also an option but brings with it an additional level of concern for venting and radon control.

Asked By user-6824154 | Apr 28 17
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