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!


5 Answers

My intake duct for the HRV seems to be collecting moisture as the insulation is wet

My intake duct for the HRV seems to be collecting moisture as the insulation is wet. There is not enough snow close to the intake so I don't think this is the issue. What else could be causing the issue?

We have been the house for five years and have never seen this problem. We use the HRV mainly in the winter.

In Energy efficiency and durability | Asked By Jefff Bean | Feb 22 14
11 Answers

Log home insulation retrofit

I'm exploring strategies for insulating an existing log home. External insulation makes the most sense to me. What are thoughts and comments about this assembly: 2x4 stud wall with closed cell spray foam covered with r-sheathing? The sheathing is needed because I think the budget will require vinyl siding. I'm not sure about air barrier and a drainage plane tho. Any comments or suggestions would be appreciated. Also thought about a nail-base sip, but I'm concerned about how to attach it, and possible thermal bridging if long lag screws were used....

In Energy efficiency and durability | Asked By Sandra Heiser | Feb 14 14
1 Answer

Sizing timber frame roof purlins

For those of you that live in a moderate snowy area such as Pennsylvania or New York and have a Timber Frame roof system of bents and purlins with t&g on top of purlins. Question is with bents on 16' centers what size purlins do you have? I imagine to satisfy the code it would be considered rafters with ceiling attached which would fall under the 240 deflection rule. For purlins on 48" centers, 15' length at 30psf (1800 lbs) a 5X7 would have .799 deflection, a bit above the allowable .75. This is telling me it would require a 6X8. Make sense?

In General questions | Asked By John H. Stehman | Feb 23 14
16 Answers

Insulated slab on grade design

Hi,
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.

In Green building techniques | 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%?

Thanks
Marc

In Energy efficiency and durability | 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.

In General questions | 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?

In Energy efficiency and durability | 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?

In Mechanicals | 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.

In Mechanicals | Asked By eric birenbaum | Feb 22 14
Register for a free account and join the conversation


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