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!


0 Answers

Global climate change solutions

Paul Hawken has written a book that identifies the most effective solutions to our climate change crisis.

The New York Times has posted a quiz on this topic -- sure, it's a gimmick, and designed to be tricky, but it's worth reading. Here is the link: How Much Do You Know About Solving Global Warming?

Here is the link to the list developed by Paul Hawken: Summary of Solutions.

In General questions | Asked By Martin Holladay | Jun 19 17
6 Answers

Roxul insulation

Does Roxul come with a paper barrier? Do I have to you put a vapor barrier down in the attic before I put down the Roxul?

In Green products and materials | Asked By Tool1 | Jun 16 17
4 Answers

Effect on mean radiant surface temperature by air heaters

I'm weighing up the pros and cons of hydronic heating versus multi split heat pumps.

Obviously heat pumps work by heating and circulating air within a space. Hydronic heating, depending on the type and position of emitters will radiate heat to people and room surfaces as well as (to some degree) heat some air and cause convection loops.

In General questions | Asked By George Kantianis | Jun 18 17
3 Answers

Flooring & Indoor Air Quality

Any recommendations for quality, affordable (< $4 / sqr ft) wood or laminate flooring that does not compromise indoor air quality? Few more specific questions:
1. Are California / "FloorScore" standards good enough?
2. "GreenGuard" appears to be more stringent - true?

I'm fine with laminate or engineered wood, click install / floating is fine. My criteria, in order, are:
- "not toxic". i.e. low/no formaldehyde / VOCs
- quality: looks good, doesn't squeak or cause more noise than a more expensive product, durable for kids/pets, etc.

In Green products and materials | Asked By Matt Draper | Jun 16 17
10 Answers

Recommended R-value for knee walls?

As part of my sealing and insulation project for my attic, I've been trying to determine what would be considered the proper r-value for insulating the knee walls. I'm assuming it's somewhere between what would normally be recommended for an area's walls and for an area's attic, but that's a lot of territory. This would be for a vented roof, and for my area of the country summer attic heat is as much a concern, if not more, as winter cold, at least for comfort's purposes.

In Energy efficiency and durability | Asked By Jeff Towson | Jun 15 17
13 Answers

Vapor barrier for existing ext. house wall (to become 4th wall for new adjacent sunroom addition with hot tub & indoor pool)

We're planning to add a stick built addition to our home which will contain a hot tub and small therapy swimming pool. We're going to include negative pressure exhaust fans and a dehumidifier system.

The three new walls will be built with Zip-R sheathing and 3" of closed cell spray foam and will therefore be very tight. The fourth wall will be the existing exterior wall of our house (currently 2*4 wood studs with fiberglass batt insulation, OSB Sheathing, tyvek house wrap and vinyl siding).

In Energy efficiency and durability | Asked By Dan Theman | Jun 14 17
3 Answers

Finding an Architect

I'm looking for an architect to design a "pretty good" simple 2-3 BR house of about 1100 SF in Orange County NY. There are some site challenges but nothing major. How should I go about finding someone aligned with GBA objectives?

In General questions | Asked By Zenterman | Jun 17 17
5 Answers

Polyurethane caulk for bottom plate to slab sealing

I've been reading the various posts on bottom plate air sealing on this site. I'd like to avoid the expense of EPDM or Denarco sill seal. I'm wondering if laying down a healthy bead of a polyurethane caulk on top of the foundation wall prior to tipping up the walls will produce an adequate seal? In addition, the bottom plate would have the standard contractor 1/4 inch foam seal. Your thoughts appreciated.

In Green building techniques | Asked By Steve Wolfe | May 5 17
12 Answers

Caulk/adhesive for exterior sheathing to top and bottom plate

I've got my box of EPDM gasket for the bottom sill to foundation wall seal. Now for the exterior sheathing. I want to seal the top and bottom plates to the sheathing. Is it necessary to use a caulk that won't harden over time, or is construction adhesive OK? I'm planning to tape all the other exterior sheathing seams with Vycor Plus. Also looking for a recommendation on foam to use for any other penetrations to the exterior sheathing. Thanks.

In Green building techniques | Asked By Steve Wolfe | Jun 4 17
10 Answers

XPS and faced fiberglass

Hi all,

I am currently finishing my basement (6 feet below grade with 3 feet above grade), cylinder block walls. My contractor has installed XPS foam board 1" behind his 2x4 wall and hasn't taped the seams. He also is putting faced fiberglass in the cavities. I have painted the interior with water proof paint, 2 coats prior to the work starting.

cylinder block > water proof pain > 1" XPS, > fiberglass > drywall

In General questions | Asked By Matt Duffey | Jun 12 17
Register for a free account and join the conversation


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