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!

0 Answers

Insulating an attic-based minisplit indoor unit & ductwork

Our home has a newly installed Mitsubishi ducted minisplit. There are now two ducted units in the attic: both the "Concealed Slim Duct" SEZ-KD12NA (there is a 3rd unit within the conditioned space that I'm less worried about). After a long-fought battle with my wife, the indoor units were installed in our attic. I know doing this was dumb but aesthetics won out over efficiency. I've posted on this forum separately about moving the conditioned space to the roof rafters. $60K bids basically killed that idea, at least for now. Right now I just want to band-aid the problem.

Asked By Brian Gray | May 26 17
3 Answers

Crawl space insulation options

House is 1-story 1200 square feet, CA climate zone 3, zip code 95062, about 1/2 mile from the ocean. Existing ventilated (passive vents) crawl space has 18" clearance, 48" OC 4x floor joists under sub-floor, perimeter foundation and piers along joists. Clay soil is damp, but downspout diversion and french drain in back yard keep the space from having standing water. House is heated by hydronic radiant heat system, on top of subfloor in 1/2" sleepers.

Asked By Phil Boutelle | May 25 17
25 Answers

Well water pumps

Is there any preferred efficient water delivery systems from a well? The constant pressure systems were mentioned sometime on this website, but I don't know if that was for space or efficiency.
Grunfos was the brand mentioned.

Asked By Steve Young | May 24 17
27 Answers

Ductless minisplit - completed Manual J


Asked By Jeremy Archer | May 1 17
2 Answers

How can I effectively resolve an issue of next door neighbor's cigarette smoke seeping into my apartment?

My neighbor's door is perpendicular to mine and about 8 inches from mine. Our apartments, long ago, used to be one big apartment before it was divided into two. One of my walls, that was used to divide the once larger apartment, is adjacent to my neighbors. I have lived here 38 years and would hate to move because of some smokers who have moved in next to me. I have asthma and my children seem to be developing it as well. By the way, I have four high-end air purifiers but they are noisy and dramatically run up my electric bill. Please help.

Asked By user-6855474 | May 26 17
2 Answers

Attic insulation in SF Bay

Apologies in advance for what feels like a question that's probably asked too often, but I haven't been able to find the answer on your site.

Can anyone offer any suggestions for finding good contractors? I live in the San Francisco Bay Area, and of all places I would think I could find some experts in green construction out here. But Yelp and Consumer Checkbook don't strike me as the best of options because the consumers who do the ratings might not know the difference.

I want some insulation in my attic, or possibly a foam roof, or someone who can guide me one way or the other.

Asked By Robert Shelton | May 22 17
3 Answers

Bathroom exhaust ducting plan

I'm in the process of roughing in a new bathroom in my basement. I'm looking for feedback on my exhaust fan plan. Bathroom is 5x11, eight foot walls. The fan will sit in the joist bay (obviously) and the duct will run about one foot in the bay to the wall, where I then need to drop the duct below the joist to run it along the wall in a chase for about 18 feet. At that point I hit a plumbing obstruction (main stack). I plan to use flexible duct for the first two feet, PVC for the next 15ish and flexible again at the end to get around the stack.

Asked By adam stanton | May 25 17
8 Answers

Rock wool vs. EPS exterior wall insulation

I am trying to decide between these two exterior insulation types for a house:
- 200 m2, flat roof
- built with Thermo brick (like f.e. Porotherm)
- ETICS/EIFS insulation system
- location: Croatia, the climate is corresponding to Philadelphia

Trying to achieve at least ~35 kwh/m2/a. Probably will end up better, since ERV is also planned (Zehnder ComfoAir Q350), and most glass will be on an unobstructed south side.

Asked By Davor Radman | May 26 17
5 Answers

Retrofitting garage to a heated shop - slab and wall details

Hi all.

I am soon to be owner of a house with an attached garage, roughly 20x30. I would like to convert the garage to a heated wood shop.

I am in climate zone 6A (Maine). I will have consistent heat in the shop, probably in the 55 degree range, bringing it up to 60-64 for working temp. I am leaning towards heat pump as heat source.

The garage is a concrete slab, the details of the footings/stems I do not yet know however.

The structure is 2x4 studs sheathed with (I believe) T1-11 exterior ply. Roof trusses (not raised heel). Stud bays currently open to inside.

Asked By Tyler Keniston | May 25 17
10 Answers

Average lighting, appliance and plug loads for PV sizing?

In doing some energy modelling for a future single-family net zero residence (in Canada), I am running into the problem of trying to guesstimate what the total lighting, appliance and plug loads will be. Because it can be different with every specific family, I'm wondering if anybody has any links or resources they can provide that offer average values for these loads that one can use. I will calculate the heating, cooling and hot water loads separately, but am hoping somebody has some suggestions for those remainders.

Asked By Burke Stoller | May 23 17
Register for a free account and join the conversation

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