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

Panasonic WhisperValue DC fan and TRB transfer box - anyone using these in the field yet?

For a while now I've been considering different ideas to distribute the air from my mini split to bedrooms when the doors are closed. I just noticed that Panasonic recently came out with a new DC motor version of their 3 3/8" deep WhisperValue fan, with selectable speeds (50/80/100CFM) and pretty low sone (noise) ratings.

They also make this transfer box that's designed to fit this fan (google Panasonic TRB -- I can't link anything or the spam filter gets me).

Asked By Nick Welch | Jun 27 17
12 Answers

Does the insulation on this wall make sense?

I live in Madison WI and am renovating my 1927 house. I have stripped the outer walls to the studs and shiplap and have been trying to figure out the best insulation scheme. The constraints are 1. in Madison they really want plastic on the inside, and 2. because of architectural details I can't put more than 1 inch rigid insulation on the outside.

Asked By user-6832947 | Jun 27 17
6 Answers

How to prevent moisture/condensation in building prohibited from using insulation?

I am building a small cottage that by code is prohibited from using any insulation (so as to prevent its use as a full time dwelling). It is a simple wood framed structure with drywall interiors that has A/C but not heat and will be used only in the summers (northeast US climate).

Asked By bsgsjkbn23450 | Jun 28 17
1 Answer

Capillary break product that will soak into concrete?

I asked a before about the need for a capillary break between the footing and the poured 5,000 lb. basement wall. I was told that I still need one. My foundation company has documentation that states it isn't need for 5,000 lb. concrete. They agree to put a capillary break in on top of the footing if it will soak in. They said one customer put Thompsons water seal on.

Is there a good product that would serve this purpose? Hopefully readily available.


Asked By Jim Sweazey | Jun 28 17
3 Answers

Attic insulation advice needed

First off, GBA is a fabulous resource for us, as we plan to build our “final home” in Asheville, NC. Climate zone 4. Our home will be a 26’ x 44’ ranch with a partially exposed, walk out full basement. Standing seam metal roof, scissor trusses, Zip system wall and roof sheathing, stucco exterior, 3’ eaves and gable ends. We will do a LOT of air sealing, greater than required insulation and high quality windows. The mechanicals and ERV will be in the basement (not in the attic).

Asked By Nancy Broadbear | Jun 28 17
5 Answers

Two minisplits in one room

I just had my mini split system installed. I got multiple opinions from the installation contractor regarding the number of indoor units in one room. There is the setup:

Asked By Bryan56 | Jun 27 17
7 Answers

Heating and cooling load calculations


So the plans for my house are complete and now I need to get load calculations done, anyone know of any good company's in Southern Ontario( Toronto area).

Would like to use Mini splits, the house is going to be tight and well insulated. So hopefully I can find someone that can understand my needs and not just try to sell over-sized unit.

With determining R-value of a wall that will have 6" of Polyiso on the outside of a 2x4 stud wall filled with R14 Roxul, what rating would I use on the Polyiso knowing the outer will de-rate some.?

Asked By Dave B | Jun 28 17
1 Answer

Roof vs. ground gutters

I'm going to be working on my grandfather's house soon to deal with moisture getting into his poured foundation. The 1940's ranch house is in Central Maine in heavy clay soil. The foundation has multiple hairline cracks in it. I think part of the cracking is due to the expansion of the clay and/or hydro-static pressure when it rains. I read the article on this site about ground gutters and I'm intrigued by the idea. I question if they are going to be more effective for a couple of reasons:

Asked By Andrew G | Jun 28 17
1 Answer

Best solar panel

I am looking for affordable solar panel for home. I have found these on this site: [Web page link deleted by editor.] Can anyone can check these and guide to purchase best and affordable solar panels for my home.


Asked By Toran | Jun 28 17
2 Answers

How to vent an insulated shop attic

I'm building a 40x96 shop. Post frame, with interior OSB, taped as an air barrier. The roof will be metal, with cellulose blown in on top of the ceiling OSB. All utilities and lighting will be using conduit, so there will be virtually no penetrations into the ceiling, except for a whole-house fan which will be insulated and sealed from the underside in winter.

There won't be soffit overhangs, so I'm not planning for a vented ridge either. Would gable vents take care of attic venting? Thinking about using two 18x24" vents on each of the north and south gables.

Asked By Adam Emter | Jun 28 17
Register for a free account and join the conversation

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