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9 Answers

2-inch foam on the interior face of the wall: What are my electrical box options?

Due to a foundation snaffu, it looks like I will have to move my 2in. EPS foam to the inside of the wall assembly. Although that seems feasible, it will add some labour and material cost (3/4" strapping everywhere, 3/4" plywood for the kitchen/cabinet area etc.)

I was specifically looking at the extra pain involved in installing electrical boxes. It seems most of the box extension rings I could find are limited to 1.5", which is a bit shy of the 2in. I would require.

In GBA Pro help | Asked By Mai Tai | Dec 2 17
13 Answers

2nd floor is colder than the 1st floor in an ICF home

Hi All,
New home, with the 'guts' built by a (rather poor) contractor.
Walls are 6-8" foxblock ICF with energy sticks. Attic insulation is R50. So should be very tight.

Single stage gas furnace. Installed by amateurs, Builder refuses to adknowledge problem and his trades' incompetence since day 1. Not having a lot of luck bringing them back, and we are speaking through lawyers at this point...let's just say that during the walkthrough we discovered the HRV inlet/outlet lines were reversed, so little/no fresh air was being drawn into the house.

In General questions | Asked By Roberta R | Nov 29 17
2 Answers


I attended a series of exceptional lectures by the German Architect Kay Künzel a few years back associated with Passive House Hudson Valley.

He had the perfect level of German arrogance or dismissiveness that really made me wonder why the things he was discussing aren't more common in my neck of the woods.

In General questions | Asked By Ethan T ; Climate Zone 5A ; ~6000HDD | Nov 30 17
21 Answers

Sizing a ductless minisplit for heating

Hi all,

I'm going to install a ductless heat pump. I settled on LG Art Cool Premier (HYV1 or HYV2). Now I need to figure out system size, and there is too much info.

I have 550 sf addition built in late '80s, which is a split lever open space, and is VERY cold (i've attached some photos)!

It has a large french door (8x10' glass, 3 sections), 7 windows, and 5 skylights. All are double glass.

In General questions | Asked By Levab | Nov 16 17
9 Answers

Ensuring a non-load bearing wall is as such (double stud wall)

Simple framing question (I think) pertaining to double stud wall construction.
Should anything be done to ensure that the 'non-load bearing' wall is truly not bearing any load, such as making it a bit shorter than the load bearing?

The specifics are as follows: A garage with concrete stem walls and interior slab. The exterior wall is load bearing on the stem walls. The interior wall (to be built) will be resting on the slab, therefore should not be load bearing. The load is a simple trussed roof, 24' oc.

In Green building techniques | Asked By Tyler Keniston | Nov 29 17
8 Answers

Sand and filter fabric over foundation drains

We're trying to put in a foundation drain that will be trouble-free for years. Pretty much following the suggestions on this site - using rigid pipe, wrapping the filter fabric around the gravel like a burrito, etc. Now we come to the question of how to protect the filter fabric from getting clogged. We asked our builder how much it would cost to get a load of coarse sand to cover the filter fabric. He came back with a price ($500) but as I asked more questions I found out that what he's really trying to get us to use is #10 gravel. I have some concerns about that ...

In General questions | Asked By William Costello | Nov 30 17
7 Answers

Rigid foam: glue vs. fasteners

I'll be installing 2 inch Thermax to the inside of my poured concrete foundation. I don't yet own a hammer drill, but I'm looking for advise on the best way to attach this material to the wall. I've read about glue only, plastic fasteners, metal fasteners, and strapping. Which are the easiest to install and will last the life of the house?

In General questions | Asked By Andrew G | Oct 31 17
3 Answers

Occupants affecting efficiency

Not a question, just a link to an article the GBA advisors should find interesting about the importance of occupant behavior in building efficiency: https://www.smithsonianmag.com/innovation/things-people-do-foil-energy-s...

Mitch Costa

In Energy efficiency and durability | Asked By Mitchell Costa | Nov 30 17
5 Answers

Zip R with corrugated siding rainscreen- need gap or furring?

I searched and saw a post here about using corrugated metal siding over rockwool insulation and it was said that a rainscreen gap is not needed because a drainage plane is already there.

Would it still be true for corrugated metal (vertical or horizontal) over a zip wall system?

And if so, can the siding (metal) be screwed to the studs and sheathing directly without furring strips? i.e. framing/cavity insulation (R19) - Zip R5 wall sheathing - vertical corrugated metal siding.

In Green building techniques | Asked By Bernard Lam | Dec 1 17
12 Answers

Cut and cobble insulation on the ceiling

Hi, i am currently renovating a 1965 ranch home in Charlotte NC, i am planning on insulating my walls with 3.5 inch reclaimed polyiso, i am getting a great deal and i will insulate my crawl space and basement walls with it also. I would also like to do the ceiling because i am buying in bulk so it going to be cheaper, i have 6 inch ceiling joists and am planning to set it between the ceiling joists with a continous layer of 2 inch polyiso over the 3.5 foam and joists.

In Green building techniques | Asked By Julian Gurau | Nov 30 17
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