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

Covering popcorn ceiling

We have a popcorn ceiling in our house with a cathedral ceiling. We would like to cover it with 2" foam insulation and sheet rock over the insulation. We only have a 4" of insulation above the current sheetrock and have a 2/12 pitch roof. Will this be a potential problem for condensation or mold?

In General questions | Asked By Jim Palmer | Oct 13 12
5 Answers

What is the safest insulation product for our 50-year-old home?

We are paying $300.00 a month during winter in our 3-bedroom home, and $250.00 in the summer with the air conditioning. It's ridiculous.

Any suggestions?

In General questions | Asked By juliet erb | Oct 12 12
7 Answers

Drainage for floating slab

We have a nearly level site with a layer of clay below about a foot of topsoil, such that we've measured water less than six inches below the surface in the Spring.

Where would you install drain pipes for a floating slab that has only 18 inches to work with (see drawing)? We were planning on installing a second set of drain pipes closer to the surface to take the gutter water. There is very little slope across the property so draining to daylight will be difficult. Do you think we need the double exterior drains?

In GBA Pro help | Asked By Elizabeth Kormos | Oct 11 12
1 Answer

What do you recommend for a crawl space vapor barrier?

Its surrounded by frost wall. Wood floor system 2' above. Will 6mil plastic do? How about fastening / sealing to concrete frost wall?

In Green products and materials | Asked By K Greenblott | Oct 11 12
8 Answers

What is the best way to superinsulate a walk-out basement?

I need an expert's opinion of my current and future game plan for my Upstate NY - Zone 6, 1968 back-split renovation.

Q1: Can I safely add 4" of exterior poly iso, since I will already have 3" of closed cell on the interior of the wall?

Q2: How can I improve this plan?

See plan details below.


In Green building techniques | Asked By Alwyn John | Sep 26 12
10 Answers

Will Water Re-Vaporize?

We are having a very difficult time figuring out a WRB for our home in Massachusetts. After reading a great deal about house wraps and learning that condensed vapor trapped behind Tyvek rotted sheathing, we became afraid to use anything but 30-lb asphalt felt, feeling that it was "smart" and "forgiving".

But as we were shopping for Siga tape we learned about Majvest house wrap. We were told that its high permeability would let out trapped water (condensed vapor) because the water would vaporize and escape. Is this so?

In GBA Pro help | Asked By Deb Davis | Oct 2 12
3 Answers

Attic insulation question

I'm doing a gut renovation of a 1000 sq ft finished attic in NJ.

I plan to spray 5" of closed cell foam between 6" rafters and 3" of foam on the attic exterior walls and put 3' x 3' doors on the side attics for access

In General questions | Asked By Bill Winch | Oct 10 12
4 Answers

Insulating a Quonset hut - (Can we make a sandwich?)

Imagine an arched metal Quonset hut, such as an older aircraft hanger. The skin of the building is structural; there is no structure under. The buildings are a set of panels which are bolted together, weatherstripped to form an arch. Each arch is bolted to the next to form the building.

Many of these structures are used a workshops or garages, we would like to use one as a studio. Typically these are insulated using either spray foam or fiberglass that is pinned to the shell, which looks somewhat like a quilt.

In Green building techniques | Asked By Doug Reid | May 4 12
2 Answers

What is the best type of standing-seam roof for solar panel installations?

I am in the process of redesigning my garage to increase my roof square footage facing south for photovoltaic solar panels. The roof will resemble a "lean-to" and will be 32 feet to the peak and 50 feet long. I plan on using full length sheets to limit seams.

I want the roof to last as I am planning to cover the entire surface. I know the roofing panels will expand and contract with temperature and this can lead to clamps on the standing seam to wear thru the steel.

In Energy efficiency and durability | Asked By Eric Pfeiffer | Oct 3 12
15 Answers

Standard house in Louisiana

Hi, I'm doing a research on single family houses in Louisiana. I'd need to find information on construction methods used for a "standard" house and energy expenditure of an average family living in it. Can someone help me please?where could I look for such information? Thanks!

In General questions | Asked By Elisa Prestia | Oct 10 12
Register for a free account and join the conversation

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