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!

3 Answers

Condensation in (conditioned space) attic, built to "environmental standards"

I am in need of a (seasoned) building consultant, familiar with New England climate, able to make an "on site" evaluation in Guilford, Ct. 06437, for an attic space that was built to environmental standards and is a conditioned space) -- air conditioning, HRVs, etc etc., for a client that has environmental allergies -- mold, fabric softener, petrochemical products etc.

There is condensation from the attic space, with leakage of water into and onto the first floor after one year. Thank you in advance. We need help.

In Project management | Asked By herbert suesserman MD | Mar 5 15
8 Answers

Insulation around a center chimney -- cape?

How would one insulate around the chimney in the attached pics? Would I start at the ceiling and just put a bunch of Roxul around it? How could air sealing work? Fireblock foam?

Bonus question: Is it too late to double stud these walls?


In General questions | Asked By stephen edge | Mar 4 15
2 Answers

Critique of cathedral ceiling and wall design - Swedish Style

Planning on building a 1-1/2 story, well insulated home using 14” I-joists as the rafters. Then running 2 x 4” horizontally. The I joist cavity will be air sealed. The 2 x 4” cavity will not. I will have an ERV. This idea is a mix of concepts seen on greenbuildingadvisor.com, buildingscience.com and the USA new wall info provided by Gregory La Vardera’s site on Swedish framing/insulation - www.lamidesign.com

In Energy efficiency and durability | Asked By Jeff Von Haden | Mar 5 15
4 Answers

New Mitsubishi Hyper Heat multi splits have finally arrived

I was having a discussion with someone on reddit and they mentioned having a MXZ-3C24NAHZ model recommended by a contractor, which I had never seen before. Googled it and, lo and behold, I find documents published just a couple months ago (like this one) describing a whole new line of Hyper Heat multi splits, sized from 20,000 BTU/hr through 48,000, and supporting 2 to 8 indoor units. HSPF rating is generally in the 9 to 11 range.

In Mechanicals | Asked By Nick Welch | Jan 13 15
10 Answers

Airspace for solar barrier

I am adding a solar barrier between layers of an alluminum roof. The existing roof is over a covered florida room. The roof system has a lower layer that is also the ceiling. The lower layer is connected to the top layer by 3 inch alumuinum I beams. The roof is insulated with porous styromfoam which is noisy when it rains and does not stop any heat penetration at all. Impossible to aircondition! I purchased a solar barrier to place between the layers of room.

In General questions | Asked By Phillip Ragan | Mar 4 15
2 Answers

How can I super insulate, air seal, and vent this space?

This is the top floor of my new to me house in zone 5. Under which is a fully insulated living space of 12 years. So right under that decking is standard 10 in fiberglass..

In Green building techniques | Asked By stephen edge | Mar 5 15
3 Answers

New home questions

I plan on retiring to BC in a few years and building " a pretty good home" . I have been reading almost everything on the GBA web site, very informative. Really appreciate all the blogs by Martin and all the others .

In Energy efficiency and durability | Asked By bert matter | Mar 4 15
11 Answers

Plans Review with a few questions

We are getting closer to building our new home. The preliminary drawings have been completed (links to plans at the bottom). We aren’t exactly building a green house, but over the last year I’ve read an enormous amount of good information from this website and a few others to help guide me in building a more durable and energy efficient house than what is typically done around here (vented crawlspaces and ducts in a vented attic are pretty standard here).

In Plans Review | Asked By Michael Geoghegan | Feb 4 15
2 Answers

Why not skip the sheathing?

I am just a layperson who wants to build a pretty good home and have been considering two wall types, but as I'm reading, I feel like I’m missing something regarding the sheathing.

In General questions | Asked By Jonathan deHart | Mar 4 15
2 Answers

Remote cabin exterior wall design

Questions on remote cabin exterior wall design. I am building a small cabin, off grid in a remote location - Yukon Canada (cold dry climate). Not for full time habitation, but I suppose that could change in my future or with a with a different owner. Wood heat only, small solar to run LED lights, 12v stereo, no running water. Dimensions 16' x 24' (2 stories). I would like to minimize the exterior wall thickness as the interior space is not especially large to begin with. Cost and ease of construction are major planning considerations.

In Green building techniques | Asked By J. Bishop | Mar 4 15
Register for a free account and join the conversation

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