Q&A: A Forum for Green Building Experts and Beginners

Q & A Instructions

[Click map to enlarge]

drawing of climate zone map.gif

Advice can depend on climate — Please specify your climate zone in your question.

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!

Ask a Question >

10 Answers

Wall assembly for an old church in Vermont

A client has an old un-insulated church in Central Vermont. She want to insulate the whole thing and turn it into a house. The builder wants to do this wall- assembly. I am concerned about dew point issues and trapped moisture. The walls are currently 2x5 studs with no insulation. Thoughts?

Asked By Robert Swinburne | Apr 18 18
1 Answer

Are solar panels today carbon footprint break-even during (and after) lifetime?

I know this is ever changing, and big effort is being made to find new ways to produce PV panels from cheaper/more environmentally friendly materials, but if I were to buy PV panels today, will they ever reach carbon footprint break-even point, when we take into account their production AND waste management?

On some soruces, I've found that getting rid of these panels is a big problem, because of the toxic materials used. How big a problem is this?

Asked By Davor Radman | Apr 19 18
5 Answers

Energy end-use monitoring system for both electricity and natural gas energy sources

I am looking for an energy end-use monitoring system that we can use in buildings that use both electrical and natural gas energy. There are a lot of really good electrical energy end-use monitoring systems, but very few that include the ability to connect to natural gas meters. The qualities I am looking for include:

- Reasonable capital cost that allow the system to be used by cash-conscience organizations (e.g. affordable housing) who are eager to reduce their energy costs

Asked By Greg Leskien | Apr 16 18
7 Answers

Minisplit for a small room

I'm considering a mini-split install in our house. I'm in Austin TX, so it's a climate that requires significant cooling. I have calculated loads and I have questions about what happens if one has a mini-split running in a low load room. It's a child's bedroom and the doors are closed all night.

The room has internal walls on 3 sides and just one 3x5 window. Currently the load calc shows it at about 3300 BTU (of course that is at design temperatures of nearly 100°F and 72°F inside).

Asked By James Howison | Apr 18 18
7 Answers

Furr-UP instead of furr-down to include ducts in the envelope?

Hi all,

I'm building a new home in south Louisiana and I've been lurking here for a few week soaking up some energy efficiency building techniques.

One of the biggest points I see on here is to include the HVAC system in the insulation envelope. But, that isn't standard practice in Louisiana for new construction ( as in, NO ONE does it in my area). I get the deer-in-the headlights when I even mention a closet unit with ducts installed in furr downs. This also goes for Framers and Home Designers

Asked By Jiggernaut | Apr 18 18
3 Answers

Frustrated with local HVAC contractors - should I outsource the design?

Hi everyone. We're building a pretty large house here in the SF Bay Area, and having a devil of a time trying to find an HVAC contractor who'll actually design things using calcs and not eyeballing it. When I finally got one to do a manual J, he had to quit the program due to a family member with a terminal illness.

Asked By mike myers | Apr 18 18
1 Answer

Cedar ceiling in bathroom?

I want to install a cedar ceiling in my bathroom above the shower over the existing Sheetrock. Is there a vapor barrier needed or will i need any airspace between the ceder plank and the Sheetrock? I want planning on using any sealant on the wood. just tongue and groove planks and brad nail it up. Thanks for any help.

Asked By Cyprus2400 | Apr 18 18
22 Answers

Insulating kneewall slopes from above

Unfortunately we are having to fix some poor quality work by insulation contractors.

How should we build baffles, or what kind of baffles/vents should we buy, to maintain >1” vent for 5’ sloped ceilings above a kneewall, which can only be accessed from the top attic?

Asked By Emerson | Apr 17 18
7 Answers

Mold Remediation

Anyone have mold remediation on a commercial building experience or been/are in the mold remediation industry?

I have a maintenance contract on this building that just started, could smell a strong mildew odor in a unit on the top floor north side of the building when completing a PO. Was doing top floor work in the south side of the building no odor. Slight odor in hall at the midpoint of the building top floor. It was unseasonably warm that day, mid 40's high temp.

Asked By T Carlson | Mar 5 18
11 Answers

Comfort Board 80 vs 110 - density worth extra cost?

For our upcoming house build using 4" of rigid mineral wool we have been quoted for both Roxul comfort board 80 and 110. Over the top of this we will install 2x4 furring and cedar siding.

The 110 has a compressive strength of 1120 PSF at 10% deflection, the 80 is only 439 PSF at 10%, using the 110 will simplify the installation of furring as it will compress less, but I don’t know that the furring installation sub would price their install any differently between the two products. (Furring install not by insulation contractor).

Asked By Chris Armstrong | Nov 16 16
Register for a free account and join the conversation


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