Community: Green building techniques

Q & A Instructions

[Click map to enlarge]

The 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!

12 Answers

Efficient shower stall design: Airflow?

So I'm kicking around ideas for efficient shower designs. Our master bath will have a shower stall that is recessed with three tile walls, and one glass wall with a glass door panel more or less flush with the side of the bathroom.

The glass wall will have three parts; two stationary panels and a door in the middle.

Asked By Lance Peters | Dec 7 17
3 Answers

Frost-protected shallow foundation near sloping landscape

i am building a house with a frost-protected shallow foundation (see attached) in brandon manitoba canada (49.8485° n, 99.9501° w) and the particular area has a very high water table. because of this, the engineer included the following note: “design assumes ground water level is consistently no less than 3’ below bottom of footings”.

Asked By Loretta Gurr | Apr 28 18
4 Answers

Old adobe home: Flooring/ heating/ insulating quandary

Hello, I am remodeling a 1930s adobe and considering flooring/heating/insulating options. Already determined is that there will be in-floor radiant with brick as finish floor.

Asked By User-6952755 | Apr 24 18
10 Answers

Small addition with helical pile foundation in Toronto Canada


I am an architect in Toronto. My client is a contractor who wants to build a small one storey addition using helical pile foundation instead of continuous foundation to save on cost.

The finished floor is raised above the grade by about 21".

My questions:

-Can I use chicken wire to support the fibreglass insulation in the floor joists as it would be difficult to finish the underside of the floor with plywood I think
-Do I need a air-barrier like tyvek under the fibreglass insulation

Asked By Lowell Lo | Apr 22 18
5 Answers

Foundation Waterproofing & Insulation Treatment

My new home design has an 8' basement and an attached garage with a 4' foundation. Is the garage foundation poured at the same time as the house or separately? On the basement foundation walls I'm planning to use spray-on waterproofing, board insulation, and a dimple mat. I'm not sure how to treat the vertical edge condition where those materials would start/stop. I used Sketchup to help myself visualize what's happening. Do basement exterior materials wrap under the garage footings and continue along the basement under the garage slab?

Asked By Bryanw511 | Apr 20 18
9 Answers

ZIP System R Sheathing vs Roxul Comfortboard

Building in the Canadian Rockies, so climate zone 5-6 ish.

Up until now I have been considering building a 2x6 exterior wall (with Roxul Comfortbatt in the stud bays) covered in 1/2" exterior plywood, installing a air/moisture barrier from Stogard over the exterior of the plywood sheathing and then fastening1 1/2" Roxul Comfortboards over the Stogard.

Asked By Scott Wilson | Apr 13 18
13 Answers

Thermal breaks when enclosing porch

I have a stone porch in front of the house (6'x25') in lower New York (climate zone 4), that is surrounded on three sides by the house and garage (fiberglass batt insulation c.2005 construction). Only the front is exposed and open. The floor is stone, presumably on a concrete slab. The siding is cedar shakes, with a 6" protruding stone chair-rail around 3' off the ground in it, and stone facing below that. The roof line continues down over this area (with a nice bead-board ceiling with high-hats in it).

Asked By j star | Apr 17 18
13 Answers

EPS, XPS or Polyiso for exterior rigid foam?

Last week I got some great information from this board on my "Taping seams of roof sheathing" question. There was some thread drift there and we started talking about exterior foam and someone suggested I use Polyiso instead of XPS for my exterior foam.

Asked By Steve Mackay | Mar 28 18
29 Answers

Rainscreens with Roxul Comfortboard IS?

Hi all.
I am planning out my wall construction for a home in zone 6. Not much rain (15" annually), but plenty of snow in winter (56" annually). Hot (and mostly dry) in summer (80sF to low 100s), cold in winter (mostly lows in the single digits, but sometimes minus teens F). My house will not have much direct sun due to northern exposure and tree shading.

All that said, here is the wall I am considering:
- wall board
- 2x6 fir studs on 16" centers, Roxul Comfortbatt (R23) between the studs
- OSB, taped and sealed for my air barrier
- house wrap for vapor barrier

Asked By Mike B | Mar 20 16
10 Answers

Rigid foam and dimple mats

My concrete contractor will be applying bituminous waterproofing tar on the outside of the basement walls up to grade. We are considering putting 4" of rigid to the exterior of the concrete after that. Someone advised us to also put up a dimpled waterproofing membrane, but is his necessary if we are applying the 4" of rigid foam?

Asked By Nina in CNY | Sep 30 17
Register for a free account and join the conversation

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