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!

5 Answers

Insulating a house

Dear Sirs: I am building walls on the inside of my kitchen and was wondering what is the best way to insulate the walls. I want to use paper backed insulation with plastic. Should I put the plastic on the back side of the wall then insulate or should I insulate and then put the plastic on top of the insulation on the inside of the walls. Any help and information that you could furnish me will be greatly appreciated. Thanks. jbrock2751@comcast.net

In Energy efficiency and durability | Asked By John Brockway | Feb 9 12
61 Answers

"What must we say?"

I stumbled on this ancient video recently and heard a sort-of contrarian statement:
"don't EVER say that hot air rises..because that AIN'T so"
(just watch the first 1:30 minutes)

"What happens is that the less dense air is pushed up by the colder air"

I had never heard it put that way ...hmmm.... very interesting

So yesterday Allison Bailes Posts a Blog on the same subject.

In General questions | Asked By John Brooks | Jan 31 12
2 Answers

Spray foam insulation - What's the best way to patch a spray foam (open cell) insulated wall?

We've had to move some plumbing lines in a freshly spray foamed (open cell foam) insulated wall. This requred us to remove some of the insulation. What's the best way to refill the insulation here without calling out the original applicator and paying his $500 minimum trip charge?

In Energy efficiency and durability | Asked By Dave Sykes | Feb 8 12
2 Answers

Is air sealing still needed when adding exterior foam?

We are currently at the framing process on our new home. ~1900 sq-ft., ICF basement (unfinished).
~1900 sq-ft main level and 800 sq-ft upper level. Located in Zone 5B central UT.

Most of the exterior will be stucco and I plan on having 2.5" of foam installed underneath on top of the 7/16" sheathing (2x6 walls) I was able to foam gun most of the sill plate to top of foundation as wall as the side bottom edge of the rim board all the way around.

In Green building techniques | Asked By Darren Smith | Feb 9 12
8 Answers

Insulating and protecting an existing brick wall

We are renovating our 100+ year old house room by room. We realize the most common and effective way to insulate is with spray foam (our brick is in excellent condition with no apparent water damage). Our problem is that because we are doing the renovations room by room, spray foam is not the most cost effective way to insulate. I can't seem to find any mention of using rigid insulation in previous articles. Can anyone make suggestions as to how to insulate with rigid (IE are vapour / air barriers required when insulating against the existing brick) and if it will do more harm than good?

In GBA Pro help | Asked By Amy Rancier | Feb 7 12
4 Answers

REScheck v. Energy Modeling

I'd like to start a discussion around the differences as well as the advantages/disadvantages of using REScheck (or COMcheck) and/or an energy model. Although REScheck seems to have been originally written to show energy code compliance cost-effectively, it is often used or mistaken for an energy model - I think primarily because it shows a "% improvement" over code, which is a commonly requested output from energy models when complying with a "above code" program.

I am curious to hear about people's experience using REScheck.

In General questions | Asked By David Epley | Feb 6 12
6 Answers

Best Practices in Mold-Resistant Bathrooms

GBA Community,
I have looked at a variety of best practices in mold-resistant bathroom strategies and materials for a moderate size full bathroom. I have landed on the following:

In Green building techniques | Asked By David Epley | Feb 2 12
0 Answers

An upcoming Passivhaus conference in Portland, Oregon

Passive House North West is planning a conference on Mach 2, 2012 at Portland State University’s University Place in Portland, Oregon.

The keynote speaker will be Jerry Yudelson. speaking on the topic “Climbing the Summit to Passive and Zero Energy Buildings.”

For more information, click here:

In PassivHaus | Asked By Martin Holladay | Feb 7 12
3 Answers

HRV Inlet Duct


I'm finishing my basement and discovered the HRV inlet duct insulation is damp at the bottom portion of the 90 deg inlet (pic attached).

Is there a better way to insulate this duct? During cold snaps here in the Pac Northwest, the rigid duct condensates, so last year, I wrapped it with insulation.

thank you

In Energy efficiency and durability | Asked By Frank O | Feb 7 12
5 Answers


I'm sorry I don't know how to get back to my original question. Air Krete's brochure says ALL GREEN INSULATION . The salesman said Retrofoam emitted gases. Retrofoams brochure says no fumes gases or emissions. Then I googled and it seemed that the words that came up said Air Krete that is made from...yes Retrofoam made by Polymaster. I guess what I want to know is IF Air Krete is made fro Retrofoam? And is Air Krete All Green? (I got asthma from black mold)

In Green products and materials | Asked By Connie Lambert | Feb 6 12
Register for a free account and join the conversation

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