Basement Insulation

[oconnor]

I am in the process of running thru the Canadian EnerGuide for Houses program. Just insulated the Attic from 0 to R60, and replaced all of my windows. We noticed an immediate change once we changed the two old windows in the basement - a testament to the value of basement air leakage remediation.

We are now insulating the basement walls to R23, with a spray foam applied to the sill plate, R 10 blue foam board to the walls and stud walls and fiberglass/ 1/2 drywall on top. Total bill for the basement and spray foam under two porch/crawlspaces was around $4300

The beauty is that the program up here will rebate me up to $2000 for the R23 basement walls alone, pro rated based on percetage of coverage! In the end, I expect to get enough of a rebate to easily pay for the labor part of the insulation bills.

Any Canadians out there who haven't looked into the program, just Google the Energuide for Houses program and check it out - even includes a rebate for upgrading to an EPA wood stove, and more.

 

[velvetfoot]

Now, I'm sure I'm not the first person to think of this, but hey I still thought of it.

I think I might indeed put another 2" of foam over the existing strapped on 2" of foam using an idea I just had. I figure I can:
-Rout vertical channels for the wiring in the first layer, wire stapling them in place
-Place the 2nd layer of foam sheets horizontally, routing out 1" recessed channels for the strapping below
-Cut out recesses for the electrical boxes. Probaby screw them into concrete
-Affix the 2nd layer in place with sheets of DensArmor Plus paperless drywall screwed to the original furring strips.

I'm not that crazy about tapconning the boxes-it would be the only place where there is a metal path to the coldness

The router has good potential to do those channels (I've tested it. A straight edge of some sorts and a couple of clamps should do it). I don't think I can do 2" thick with the router for the electrical boxes-I wish I could. Would there be any suggestions how to make a nice opening so a box could fit in there snugly? The roto-zip and others are probably geared toward cutting out drywall thickness. Maybe just a regular old drill bit: it might go through it easily. I'll have to try that tomorrow.

This would result in an R20+ wall that is solid, no voids. Even with the 2' on center furring strips, I bet it will still be rugged, ie, you could run into that wall pretty hard without putting a hole in it. I think it'll be way more rugged that putting drywall on the furring strips and have a void. Plus there could be air currents. (rationalizing costs here ). Couldn't really hang anything heavy off it though.

Anyway, call me crazy, but I think it'll work. Not cheap, but a thin, rugged R20 wall with virtally nothing organic and nearly no thermal bridging.

Waddya think?

Here is what I am starting with:

 

[kenny chaos]

If it's an unheated basement, does a person still want to insulate the walls or the ceiling?

 

[begreen]

My crawl space is unheated. I turned it into a conditioned space: insulated the walls, sill plate and the rim joist (but not the ceiling). Now it never gets below 60 down there. It makes for warmer, draft free floors and there is less duct heat loss so the heat pump has to work less.

 

[kenny chaos]

Thanks for sharing but this is an old stone house and I'd rather not cover the walls. Would it be wrong to insulate the ceiling?

 

[velvetfoot]

no, it would not

 

[kenny chaos]

But I read somewhere that the basement could get cold enough to freeze water pipes?