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6 Answers

Wall and roof assemblies - mineral wool or foam?

This site is such a great source of information - I've been planning a weekend house (straw bale, zone 6) for the last several years, and this site along with Dr. Joe's BSC archive have provided a great education on all aspects of sustainable residential design. So that's a thank you to everyone who frequents and posts here.

In Energy efficiency and durability | Asked By Devin Ratliff | Oct 7 13
9 Answers

Drain tile and stepped footings

Our house will have a walkout basement and in the design diagrams the architect has placed the exterior drain tile at the same level as the footings even where the step footings are located. At a couple of locations this places the exterior drain tile close to 5 feet beneath the slab. Does this make any sense?

In General questions | Asked By Tom Peterson | Oct 8 13
4 Answers

Open cell vs closed cell

I am renovating my daughter's room located on the second floor of the house. I got a estimate from a spray foam company. They recommended 6 inch open cell in between my ceiling 2x8 rafters. On the west side exterior wall with a brick wall in the center of the wood frame (chimney) they want to apply 3 inch closed spray foam in 2x4 wall. I believe I am in zone 4a. My question is: is the open cell the right product and do I need a vapor barrier?

In GBA Pro help | Asked By SAMUEL FILINCIERI | Oct 7 13
5 Answers

Wood frame wall details

welcome everybody

My question is, how good it will be wall like this:

from inside

1/ drywall
2/ service space for wire (like Swedish houses) -wood frame 2x2 (fill or not with insulation)
3/ vapor barrier (plastic)
4/ 2x6 frame with mineral wool - http://blog.lamidesign.com/2012/01/what-you-don-know-about-mineral-wool....
5/ OSB 1/2"
6/ 6 -8" mineral wool
7/ thin coat silicate stucco

I don't have official data but winter is about 4-5 months with some -5°C to -10°C [23.0°F to 14°F] mostly, but can be -20°C [-4.0°F] for week or two.

In PassivHaus | Asked By peter abramowicz | Oct 4 13
5 Answers

Exterior siding details

My house is a 1500 square ft bungalow located on Lake of the Woods in Ontario near the Minnesota border (Climate Zone 7) . Before I purchased the house the previous owners replaced all the windows with triple pane pane windows but had the installers build them out 1.5" with intentions of adding exterior foam when the siding was to be replaced. I have since gutted the entire main floor and rewired, plumbed and insulated with 3.5" of closed cell spray foam in the walls. I added a couple more windows and a set of patio doors and stuck with the 1.5" build out.

In GBA Pro help | Asked By JP Patrick | Oct 2 13
3 Answers

Unvented and unconditioned attic, is this to code and is this a good idea?

New construction in climate zone 6a, north/central New Hampshire. House specs:
-r45 walls
-approx r70 attic consisting of loose fill cellulose in rafters above drywall (the ceiling air barrier)
-goal of 0.6 ACH @ 50 Pascal

The plan is for an unvented and unconditioned attic:
-sealed below at the drywall
-Advantech sheathing on trusses
-roof underlayment either RoofTopGuard (http://www.rooftopguard.com/en/home.html) or heavy felt with Grace Ice and Water first 3 feet on edges, strapped, then metal roof (very simple A frame roof, rectangular 24x32 two story house)

In Building Code Questions | Asked By Brian Post | Oct 7 13
3 Answers

Interior 'vapor barrier' in Eastern NC

I'd appreciate any help I can get on this one. Just purchased a home in coastal North Carolina. It was built in 1985, when for some strange reason, it was code here to apply a layer of poly to the inside of the stud wall before drywall. The smarter contractors waited until rough inspection was completed and then cut out the poly before drywall was applied. Unfortunately, that didn't happen often enough. I've heard horror story after horror story about 12-30 year old homes rotting from inside out in this area.

In Energy efficiency and durability | Asked By Colin Shine | Oct 6 13
1 Answer

Rotted sill plate replacement — no tie-downs


1880, balloon framed foursquare. An old porch which sometime in the early 20th century was turned into an addition and a full foundation added (block with hollow core..thicker than modern block) with a porch/deck above. Turns out a small leak in the copper deck has allowed water to come in for quite some time, disintegrating the sill plate and rim joist (actually there is no sill plate just a double 2x8 rim joist).

In Building Code Questions | Asked By Geoffrey Cook | Oct 6 13
1 Answer

Porch / deck over conditioned space — insulation question

Ok and thanks in advance. I have a small deck/porch located directly over a bedroom on the first floor. The area is approx. 5'x12' and it was uninsulated since the very early 1900's when the addition was added. Here's a little diagram. I'm wondering:

In Energy efficiency and durability | Asked By Geoffrey Cook | Oct 7 13
2 Answers

Low slope attic/cathedral ceiling ventilation in climate zone 3c

I have been remodeling my 90 year old bungalow in Oakland, Ca. It has never had ventilation in the attic and shows no signs of problems. I have converted about a quarter of the roof to a cathedral ceiling with 4" of polyiso foil faced insulation carefully foamed into the rafter bays and with a 1 1/2" space above the insulation. in the rest of the attic, I added a foot of blown in fiberglass after foaming/caulking any gaps I could find and reach. We are getting ready to redo the composition shingle roof but none of the ridge vents I have found are recommended for my 2 1/2 / 12 roof slope.

In General questions | Asked By Andy Kahn | Oct 2 13
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