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8 Answers

Steel roof: to sheathe or not to sheathe?

I'm considering a steel roof for our new house build (hip design, 7 or 8:12 pitch) and I'm wondering whether sheeting first with OSB or plywood and a moisture barrier makes sense? I've done a little reading and it seems there are some who are in favor of sheeting and others who see it as a waste of time/money.

The main concern seems to be with moisture condensing under the roof when cool night air drops below the dewpoint of air in the attic. To this I question:

In General questions | Asked By Lance Peters | Apr 19 17
6 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

In Energy efficiency and durability | Asked By user-6822325 | Apr 22 17
3 Answers

Air or vapor barrier for attic (using cellulose)?

Is there a certain air or vapor barrier that I should install before hanging ceiling sheetrock? The attic will be insulated with blow in cellulose. The attic will be vented at the soffit and with a ridge vent, nothing else. House is in zone 5. Probably R-40 to R-50 in terms of the amount of cellulose. I am looking at using the Certainteed smart membrane like I will on mineral wool walls.

In Green products and materials | Asked By Ralph S | Apr 24 17
1 Answer

Moisture control / insulation for new cinder block shop with loft / den.

Hello Folks

I've been reading through the forums for an answer to this question, but haven't been successful in finding one. I'm building for the first time, so this is a learning curve for me.

I live in west Florida, and have a project in the works. I'm going to be building a 55ft x 38ft workshop, that will be 2/3 work space, and the remaining 1/3 will be a loft / den living space with a small kitchen, laundry area, and bathroom. So around 1400sq ft. I am planning on controlling climate with a 3 air handler mini split system.

In General questions | Asked By brew0688 | Apr 24 17
11 Answers

2x4 rafters, skip sheathing, no insulation, help with roof choices

The shingled roof on my 1940 farmhouse in Zone 3b is due to be replaced. My wife and I are considering the virtues of metal for our very hot, very dry climate where electricity often exceeds $0.40/kw hr.

I plan to remove what little insulation is presently on the attic floor. The hvac ducts are also in the attic with little insulation and are likely poorly sealed.

In General questions | Asked By Edgar Pankey | Apr 20 17
3 Answers

Fiberglass-backed polyiso got wet, now moldy on surface: to keep or not to keep? Remediation?

A few months ago I chatted back an forth with Mr. Martin Holladay about my project... I have progressed on it since then, but have ran into an unforeseen problem. Let me bring you up to speed:

I am building an apartment underneath a lean-to roof coming off of a post-frame shop building in climate 3. I purchased some used poly-iso foam boards to use as insulation on the underside of the existing metal roof. At this time I have reached this point (Layers shown from top to bottom):

Metal roof
2x4 purlins (with subsequent 1.5" air gap)

In GBA Pro help | Asked By John Peeper | Apr 23 17
2 Answers

Double sheetrock + green glue + Membrane

I am going to be using mineral wool, a certainteed membrane, and possibly 2 layers of sheetrock (1/2" or 5/8") with green glue between them. Is there going to be any problem with this design in terms of the membrane's performance? I don't want moisture problems by using 2 layers of sheetrock + the green glue.

In General questions | Asked By Ralph S | Apr 24 17
18 Answers

Warmboard with Ductless System?

Newbie here, so pardon my ignorance.

We are about to start designing a home in the DFW area (Zone 3).
Home will be a 2-story open concept with about 5,000 to 5,500 SF, properly insulated for the area. Despite the size, plans are to go with about 20 KW of grid-tied Solar Panels with a Powerstation 247 system.

Wife wants "Warmboard" as the heating source for at least some of the areas. I would like to have a VRF Ductless System for cooling and heating. Is there anyway to marry the two so that we stay "married" ? :-)

In Mechanicals | Asked By Rodgo | Apr 19 17
8 Answers

New house build, SIPs?

New member here, we are planning to build a new house this summer and I'm exploring my options for wall systems. I plan to do the framing myself. House will be roughly 2500 sqft in Ottawa, Ontario Canada. Not the coldest place to build but not far off, and just for kicks it gets pretty hot and fairly humid here in summer as well.

In Green products and materials | Asked By Lance Peters | Jan 15 17
0 Answers

Standard (non-custom) window sizes?

In the interest of getting the "most bang for my buck," I have been trying to find "standard window sizes," as opposed to what is generally advertised as "custom" windows... Perhaps this is something that is available in high performance windows, perhaps at widths which correspond to common framing widths such as 24" OC, 16" OC, etc. I would be happy to design around these parameters, but it seems that most high performance window manufacturers also tout "custom sizes." Does anyone have a lead on standard high performance window sizing?

In Green products and materials | Asked By Ethan T ; Climate Zone 5A ; ~6000HDD | Apr 24 17
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