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

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

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

If you want to post a question, 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!

6 Answers

March for Science

I'm sure that many GBA readers spent yesterday at their local March for Science protest. My wife and I, along with several friends, joined researchers, academics, middle-school science teachers, and lots ordinary people who care about the planet (and who use accepted means of separating truth from falsehood) at one of the hundreds of marches that happened all over the world yesterday.

Lots of good signs. Among my favorites: "I can't believe I'm marching for facts" and "Knowing Stuff is Good -- Seriously, why do I even have to march for this?"

Asked By Martin Holladay | Apr 23 17
4 Answers

Can straw bales be used on the exterior of a shipping container home?

I am interested in building a shipping container home. Insulation is one of my biggest concerns. I have read a lot about the benefits of straw bales. I am very interested in using this as the exterior insulation, but have not found any info pro or con. Any help will be very beneficial.
Thanks for your info.

Asked By OrrinH | Apr 23 17
8 Answers

Roof membrane in ceiling?

In a commercial application we are putting a new floor over an existing roof that has an EPDM or TPO roof membrane on it. We feel this membrane should be removed for a variety of reasons, but, are getting questions from builders if it's necessary. If left, it would above a dropped ceiling, below the new floor deck. Is there a code addressing this or literature backing up it's removal? Thank you.

Asked By BryanD14 | Apr 24 17
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:

Asked By Lance Peters | Apr 19 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.

Asked By Ralph S | 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.

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)

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.

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" ? :-)

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.

Asked By Lance Peters | Jan 15 17
Register for a free account and join the conversation

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