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!

16 Answers

Insulated slab on grade design

I have several questions about the Insulated slab on grade design. I have seen it done several ways on the internet and really need some advice. A little background on the project.

Asked By Thomas Perkins | Feb 17 14
2 Answers

I am interested in the Condensation Resistance values that I see on different windows

I see that the NFRC has these calculated for all different windows.

Does anyone know how to correlate the CR value with actual temperature and humidity levels in the house. Any calculator out there somewhere?

i.e. what CR value is needed to prevent most condensation on a window when the outside temperature is -10 degrees and the inside temperature is 70 degrees and the indoor RH is 25%?


Asked By Marc Sloot | Feb 22 14
11 Answers

Who are your favorite online suppliers?

Hi all,
I'm sniffing out a story for Fine Homebuilding on how progressive builders are acquiring their progressive materials for remodeling and new construction.

There are lots of online suppliers for building materials these days: Conservation Technology, Energy Federation, Energy Conscious, Small Planet Workshop, GreenDepot, even Amazon.

Asked By Justin Fink | Jan 8 14
2 Answers

Does an AC compressor located in full sun work harder than one located in the shade?

Our AC compressor is located on the south side of our Florida home and it seems to me that if it were shielded in some way it would not have to work as hard - is this correct?

Asked By Chuck Mucciolo | Feb 22 14
1 Answer

Heat pump ratings for marine climate in Seattle?

Which heat pump brands have the highest ratings for efficiency and durability and value for a 1500 sf single family home in Seattle?

Asked By ken jensen | Feb 23 14
1 Answer

Can you recommend a kitchen range hood exhaust fan that is more than just a metal flapper?

Something that actually closes tightly and has some insulation value?
Thank you.

Asked By eric birenbaum | Feb 22 14
2 Answers

Mineral wool revisited

I have been following the discussions about mineral wool insulation below grade (Roxul Drainboard) and have the following questions/information to share.

1) Cost and availability
From one of the posts I got the impression that Roxul would be around the same ball park as rigid foam regarding cost (per Jonathan Ram, Roxul) and that they are serious about improving availability (per John Straube). Well, so far I have only found one supplier in my area (Minneapolis/St. Paul) that could get it, with a minimum order of a pallet (432 sq ft) at a cost that seems way out of the foam ballpark.

Asked By Stephen Martinson | Feb 20 14
16 Answers

Window installation — sealant offgas issues


About a month ago, i had some windows installed in my basement. They were installed on a cold day, about -5 degrees Ceclcius (20-25 Fahrenheit). The weather here has gotten unseasonably colder. The sealant used to put the windows in place was Mulco's supra expert, and seems to be dry on outside, but some areas are still soft.

Asked By cory b | Jan 7 14
6 Answers

The old ‘keeping the room above the garage warm’ conundrum

I have a 7 yr old 2 story colonial in Zone 4/5 (just outside of NYC)

The room above the garage is cold, I opened a 1ft sq up and found R38 but it hadnt been attached the the floor joists above so it was resting compressed on the garage ceiling, so rather than tear the ceiling down I blew in cellulose to fill in the floor joists.

So result floor warmer but still cold.

Question, if I screwed and taped 2" foil faced poly iso sheets to the garage ceiling would that be enough of a thermal break to make it any warmer,

Asked By Darren Finch | Feb 20 14
4 Answers

About to build a coastal home in zone 2B and would like to be off the grid as much as possible & be hurricane resistant.

We have never done a new-build and never had to deal with hurricane potential. We want to start with the most off the grid build possible for our area (Corpus Christi, TX). This will be a retirement property for us so we do need to consider budget. What are the most cost effective ways to be energy efficient while also being able to withstand high wind & flood potential?

Asked By Ken Smith | Feb 19 14
Register for a free account and join the conversation

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