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4 Answers

Using closed-cell foam in a double stud wall

Joe St Denis

We live in north Central Alberta, zone 7-8. We want to build a 1 1/2 story house with a walk-in basement. Hillside home on a lake lot with west, north, and part of south basement wall open.

I have spent hours reading on how to best insulate walls and ceilings (which I find can be and has been challenging). After reading many articles I was planning to build a double stud wall using 1/2 inch plywood on the inside stud walls which we could cover later with wood or thin gyprock. Use scissor trusts for a cathedral ceiling, also lined on the inside with plywood.

In Energy efficiency and durability | Asked By Joe St. Denis | Jun 4 15
12 Answers

What is the best interior cavity insulation to use with rigid exterior foam insulation?

I plan to build a one-story house in northern Ohio. My initial thought is 4 inches of exterior rigid foam, over OSB or plywood sheathing, with 2 x 6 interior walls.

(I like the rigid foam, because I believe that my builder, who is meticulous and whom I trust, can install it. If I went with a double wall construction and dense-packed cellulose, I would be at the mercy of a subcontractor. And, since fiberglass batts are still cutting edge technology in this part of Ohio, I'm not confident that I would be able to find someone who could properly dense pack a 12-inch cavity.)

In Green building techniques | Asked By James Timmerberg | Jun 4 15
3 Answers

Heating strategy for an externaly insulated 9" solid wall

Hi I am a newbie to
I live in the south of the UK and live in a large detached 1920's solid wall house and last year I had 4" of enhanced polystyrene insulation put on the outside. It rarely gets very cold as it dose in parts of the US or continental Europe What I am seeking to find out is the most economic strategy for heating..

In General questions | Asked By John Richardson | Jun 4 15
1 Answer

ERV -- Independently ducted with a single supply and multiple returns?

I am looking to add an independently ducted ERV to our 20 year old home. Fortunately, I have a lot of attic space which should make it easy to set up the ERV to cover the whole house without having to hook into our HVAC system (which I would prefer not to do). However, by not hooking the ERV to the HVAC system, the fresh air being supplied into the home will not be conditioned (other than from the fairly minimal air exchange process in the ERV).

In General questions | Asked By Brian Jackson | Jun 3 15
3 Answers

Proposed flat roof design / wall design

Proposed assembly for a heated shed / barn - Worcester MA area

when inside it will have the look of a barn, raw and unfinished - all insulation to the outside.
It is a little outside of the box for most contractors here. Heated

Almost all recycled materials or sourced local, Persist(?) style of Construction -

Roof is tricky - (Flat roof, can buy wedge foam, but cost is unknown))

see pics 30x50

- Truss

- Pine board

- Plywood

- Ice and water to wall assembly (?)

- 8" foam

- Plywood

- Rubber roof

Or should it be this .. 2 adjustments

- Truss

In GBA Pro help | Asked By Howard Kelley | Jun 2 15
7 Answers

Taping overlaps in roof vapor barrier?

I'm adding insulation to the exterior of my roof. The stack will be as follows, from bottom to top:

5.5 inch Roxul in rafter bays (underside of roof)
existing sheathing
vapor barrier (solitex mento)
3 inch poly iso
4.5 inch nailbase (Hunter panels: 3 inch poly iso, 1 inch vent gap, .5 inch osb)

Today the roofers came to start- they removed old shingles and put down the vapor barrier.

In General questions | Asked By Hari Kamboji | Jun 3 15
2 Answers


We are purchasing a house. It has steel siding that is peeling and is likely defectively manufactured. The current home owner has been unsuccessful in getting the manufacturer to replace the siding.
Would the cost of removal of the current siding be the same regardless of the type of new siding that is installed? What type of siding is best? What type of siding meets the "pretty good house: standard?

Thank you for your assistance.

In Energy efficiency and durability | Asked By Ann Henning | Jun 3 15
8 Answers

Solar passive overhang design on skillion/clerestory roof?

My husband and I are in the design phase with an architect in Washington, PA (hour south of Pittsburgh..Stiller country). We are attempting to build a solar passive home with SIPS. Our architect has been great. He admitted early on to not having done many solar passive homes, which is expected, Pittsburgh is not necessarily a hub for efficient home design. So I've been doing alot of the calculations (which is fine by me, makes me feel useful).

In Energy efficiency and durability | Asked By Melanie Beth Scott | Jun 2 15
8 Answers

Is there an energy efficiency penalty for an oversized dehumidifier?

If i buy one that is oversized for my basement it will presumably run fewer hours a day at higher wattage, is there any penalty or lower effectiveness on this?
The one i am considering is 1.85L/kWh energy star rated compared to another 1.85L/kWh unit.

In Energy efficiency and durability | Asked By Alan B | May 22 15
6 Answers

Add exterior foam -- but (woops) poly sheeting?

This is a follow up to my question from yesterday - "Add exterior foam -- but paper-faced batts?"

Well, at the advice of my builder I cut some test holes and darn.. poly sheeting over the batts, not kraft paper as I thought.

So the same question applies - what are my options, if any, for adding exterior insulation during this window replacement project?

Thanks again.


In Green building techniques | Asked By Kyle Hollasch | May 27 15
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