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4 Answers

Energy-efficient envelope advice

I'm building a high efficient cabin in climate 6 (dry) and have got a ton of helpful info from this site. I was hoping the the experts that frequent the site could make comments or give advice to improve the design. Also, let me know if there is something that doesn't mesh with the current building science. Any input would be helpful, thanks.

Foundation System:
Sealed crawl space with vapor barrier and 4” rigid foam insulating interior foundation walls.
Ground Floor System:
I joists with R30 batt insulation.
Above Grade Walls:

Asked By David Voros | Mar 29 17
2 Answers

What experience has anyone had with MLI (Multi Layered Insulation) in attics?

Specific product by Yellow Blue. Also their solar fan for attics

Asked By DaveDish | Mar 30 17
9 Answers

Critique this rough floorplan

We are in beginning stages of choosing an architect/project manager, but we have some wishes on how we want the floor plan to be.

Being amateurs, I'm sure there are mistakes. Please critique.

Our goals, wants and needs:

- make the house as small as possible, ut with enough room for everything we need/want
For example, we want a study, though that is not common practice here. We took that good practice from USA and like it a lot.

Asked By davor radman | Mar 28 17
3 Answers

HRV system design

Building a new home located in Osaca, Ontario (East of Toronto) just in early design stage. Single storey with full conditioned walk-out basement (2200 sq’ per floor). Truss attic with blown cellulose insulation. Hoping to build pretty good or if possible Net-Zero home. Looking at HRV or ERV design for the home, I have a couple questions.

1. The Kitchen and living area are open to each other both roughly same size (15x18). I assume its fine to have the fresh air at one end and the exhaust (kitchen area) at the other? No problems being in the “same room “.

Asked By Dave B | Mar 30 17
2 Answers

Rough Lumber Rainscreen

I'm considering materials to use for a rainscreen under 1x8 shiplap siding. Will the variation in thickness in rough lumber telegraph through the siding?



Asked By John Ranson | Mar 30 17
5 Answers

Floor above unconditioned space

Firstly thanks for the feedback on my previous roof assembly post. This question relates to the floor of the conditioned area (ceiling of a garage/carport). Thankfully no ducts, just wires and plumbing in a few locations.
By way of background, its climate 4C (near Vancouver, Canada) and a small building used as a holiday home, not fully occupied in Winter. The occupied conditioned space will sit above both an unconditioned garage and cantilevered over a carport.
Designers build up from conditioned side down:
- ¾ OSB T&G
- Poly sheet
- 9.5” I Joists on 16” centers

Asked By Quinn Sievewright | Mar 29 17
7 Answers

Zip panels vs. liquid WRB

I was curious - what option might be more cost effective?

1.) sheathing with OSB and then using the Prosoco joint compounds and CAT 5 liquid WRB over the entire surface...


2.) sheathing with zip system panels and then using the Prosoco products to seal the seams.

Asked By Brian W | Sep 25 15
4 Answers

Rim joist with exterior EPS

My home has 1" of EPS on the exterior walls and covering the rim joist. The rim joists are uninsulated on the inside. If there was no exterior rigid I'd use a combo of rigid foam board and batts on this inside, but because of the exterior insulation, I'm concerned about creating a vapour sandwich.

Is the best approach here to air seal from the inside with caulk or canned foam, then add FG or roxul batts to allow inward drying?


Asked By ryan ryan | Mar 29 17
24 Answers

Wall moisture monitoring

I'm diagnosing a tricky moisture issue. Part of the process has involved the use of wall cavity humidity and temperature probes. I have some data and I'd like to "peer review" some of the findings in broad strokes.

First off, this great article got me thinking:


Asked By Rob Simpson | Mar 6 17
1 Answer

Rigid foam over fiberglass wall batts in attic

I'm amazed at the info this site has. Hopefully someone can give me some insight on a couple of problems I have:

I have a two story home in Texas. In my garage attic, I have 60 x 10 feet of vertical walls facing the hot attic space. These walls are of 2x4 construction with vertical unfaced fiberglass batts held in place with a thin mesh.

1) The interior walls on the backsides of these attic walls are warmer to the touch than other walls in the room. There are many voids in the fiberglass batts and I can see the backsides of many of the outlet boxes.

Asked By Nigel Campbell | Mar 30 17
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