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6 Answers

Closed-cell spray foam


We are considering putting closed cell spray foam based in our unvented crawl space based on an energy audit. I got a second quote and the numbers vary wildly and the only difference is the depth of the foam (which makes sense more foam = $). How do I know what is the correct thickness of foam? One quote is for 2 inches on the ceiling and 1.5 inches on the walls and the other is for 3 inches on both. I don't want to waste money on 3 inch if it isn't necessary but I don't want to not see a significant change due to too little spray foam being used. We are in Long Island NY.

In Energy efficiency and durability | Asked By Michemez | Jan 10 18
8 Answers

Code official wants polyethylene for interior of EPS insulated wall


I'm planning a new house construction in New Brunswick, Canada and am looking for some input from the knowledgeable folks here. The house is located in the southern part of New Brunswick. (Climate zone 6A I think)

My planned wall assembly is:

3" of EPS foam on the exterior (My builder is recommending 3" Silverboard XS, which claims to be R-5/inch)
OSB Sheathing
2x6 framing with Cavity Insulation - cellulose or blown fiberglass
Interior Drywall w. Paint (Air barrier)

In Building Code Questions | Asked By Chris Burpee | Jan 10 18
2 Answers

Best way to improve airtightness when re-siding

I'm working on a renovation project where the client is re-siding their whole house in cedar shingles, as well as redoing the roof, adding some dormers, etc. The new roof is probably going to be a hybrid ccSPF+batt insulation type deal. The shingles will get a small rainscreen gap with either corrugated battens or a spacer mat.

I'm assuming the existing sheathing is plywood or OSB. 2x4 walls, probably with batt insulation. For now, let's assume that they are not going to be adding any exterior rigid insulation.

In Energy efficiency and durability | Asked By Brendan Albano | Jan 8 18
11 Answers

Attaching siding to 1x4 battens (furring strips)

I am interested in having 8" smart side lap installed on a rain screen made up of vertical 1x4s. The LP application guidelines say the following: The framing shall be of adequate thickness to accept one and a half inches of nail penetration. I am using one and a half inch roxul and the stud spacing is 16". I feel confident this would work fine but how many contractors will do an installation that doesn't follow the manufacturer's policy. Also would this be a violation of general building code? The nail penetration would be three quarter inch.

In Building Code Questions | Asked By Cragged | Jan 8 18
3 Answers

Detail for porch slab against foundation slab insulation?

I am looking for detail recommendations for where the front porch slab meets the entry foundation slab with slab insulation. The entry foundation is a monolithic slab and is required to have R10 rigid foam insulation around the perimeter. The porch will sit 3 inches lower than than the entryway slab. I had thought about covering the insulation with stone veneer but with the insulation plus the stone this will stick out several inches from the wall which seems undesirable in way of the entry door.

In Green building techniques | Asked By WashingtonWolverine | Jan 10 18
10 Answers

Radiant heat in a single room with a small water heater?

Been reading a learning here for some time, thank you, but now I have a question of my own. I bought a 2,500 ft split level home in southern Wisconsin. The house had hot water radiant heat and no A/C. The boiler was from the 70's and there was a flat roof. We have a sun room off the back of the house that is 10X16. It is on a slab and the owner added radiant in floor heating under the granite floor tiles.

In Mechanicals | Asked By MichaelB303 | Jan 6 18
4 Answers

New construction: Integral garage insulation help


I'm building a house in Zone 5 that will have a 2 car integral garage with living space above 1/3 of the garage ceiling and will share a rear wall and 1/3 of a side wall with main house.

My plan is to use the Zip sheathing system (walls and roof) for the entire house with 4" rigid foam attached to the zip sheathing on the exterior of the walls and then cellulose in 2x6 bay studs.

The shared wall sections will be 2x4 and I was thinking to use 3" closed cell spray foam here.

In Energy efficiency and durability | Asked By Wayne321 | Jan 8 18
2 Answers

Is a rat slab necessary?

I'm building a cabin in the NC mountains with a conditioned crawlspace. I'm trying to figure out if it makes sense to spend the extra money on a rat slab or not. In my situation, the benefits seem rather minimal. In terms of the crawlspace layers, I'll definitely have a 4 inch base of crushed stone, then 4 inches of rigid insulation (R20), and then a premium 20 mil polyethylene vapor barrier.

I'm under the assumption that a rat slab mainly has the following benefits:

In General questions | Asked By Rodrob15 | Jan 9 18
3 Answers

Wall System for Climate Zone 6B: Off-grid, wildfire and earthquake prone with dramatic temperature fluctuations

My wife and I are in the planning/design stages for a passive solar, solar-powered single family home of approximately 1,600 sq. ft., at an elevation of 6,500' within a national forest in southwest Montana (Climate Zone 6B). The site is relatively remote and off-grid--nearest electrical hook-up is 8 miles distant. The area lies in a seismic zone and owing to dry summertime conditions, experiences periodic wildfire activity, the risk of which is made worse by the expansive area(s) covered by standing and fallen beetle-killed lodgepole pine trees.

In General questions | Asked By Jack Lundberg | Jan 9 18
1 Answer

Manufacturer's instructions

Concerns frequently crop up about not following manufacturer's installation instructions, both from a code and warranty perspective. I thought some discussion around this might bring some clarity. Here is my take on it:

In General questions | Asked By Malcolm Taylor | Jan 9 18
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