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Finishing Basement. Leave or replace existing insulation?

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  • Mar 30th, 2018 8:24 am
[OP]
Deal Addict
May 2, 2006
1310 posts
240 upvotes

Finishing Basement. Leave or replace existing insulation?

Hi,
I am starting to get the ball rolling on finishing my basement. The house is 7 years old and currently has R12 insulation on the basement walls, which was installed by the builder. There are 3 registers in the basement that I closed/covered years ago. I've been digitally monitoring the temperature in the basement over the winter and it averages 21 degrees. My question is whether to leave the existing insulation and frame over it or rip it out and replace it with foam board and batt or just spray foam it? My understanding is that alot of the heat loss in the basement comes from the concrete floor, so I'd also have dri-core installed as the sub-floor, which should help with the temperature.

Thanks in advance for any advice.
8 replies
Deal Fanatic
User avatar
Oct 16, 2008
9319 posts
3694 upvotes
Maple
Before you finished your basement, don't forget to tape off your furnace and duct connections/gaps with aluminum tape.
I hate to speculate. I hate to forecast. I am just proactive.
Deal Addict
Nov 9, 2008
1851 posts
871 upvotes
Toronto
My preference would be to rip out the existing builder crap insulation - odds are it is soggy and has mold presence, as they typically use fibreglass directly against the foundation with vapor barrier overtop.

Spray foam would be your best option, but most expensive. Next best option would be 2'' XPS direct on foundation, then frame infront, then Roxul in cavities. I've seen others post that the price of XPS has risen drastically over the past few years, so when you factor in everything going with sprayfoam is not substantially more expensive.

If you are in Ontario, you would be wise to take advantage of the rebate program currently running, which would make spray foam very affordable.

I previously roughed in and began finishing of our basement - 2x4 framed walls, R14 Roxul batt, covered and sealed with vapour barrier. The basement was left this way for 5 years while we concentrated on other portions of the house. When I finally got around to beginning to finish the basement very early last year, I found mold growth within the wall cavity. I ended up ripping out all the Roxul (sold on Kijiji) and we had the basement sprayfoamed with 2-3'' of 2lb closed cell foam. While the basement was fairly cozy with just the Roxul previously, the difference with the sprayfoam is drastic - the basement is hands down the warmest area in the house and now where we spend the majority of our time.

Regarding the floor and heat loss, I should also mention that we used Luxury Vinyl Plank (Torlys Everwood) with cork backing directly on the concrete slab. We are very happy with it - even in the winter months floors are about as cozy as our hardwood upstairs. We do have a vapour barrier beneath the basement slab which all but eliminates the moisture/humidity infiltration from grade however.
Deal Addict
Dec 17, 2007
2619 posts
1594 upvotes
Alliston, ON
I'd do spray foam. With the rebates from GreenOn ($2/sq ft) , I'm sure it'll come very close to being the same price as using Roxul. Also don't forgot to spray foam in the rim joist area's.
Deal Addict
Dec 25, 2007
1268 posts
751 upvotes
GTA
dricore flooring is expensive. You can use Delta FL with OSB instead.
[OP]
Deal Addict
May 2, 2006
1310 posts
240 upvotes
Thanks jacquesstrap for taking the time to reply. Excellent information! With the rebate program the spray foam seems like the way to go.
Deal Fanatic
Nov 18, 2005
5056 posts
1437 upvotes
Kitchener
For the Green-on sprayfoam rebate, you'll need R20 which is just over 3" thick. I just had Peter from VIP Foam spray a basement for me and the cost was roughly $1000 more after rebate than going with Roxul R20. it's very warm, I have to close all heating ducts and open the windows when I'm working there
20180119_175237.jpg
[OP]
Deal Addict
May 2, 2006
1310 posts
240 upvotes
Drthorne wrote: For the Green-on sprayfoam rebate, you'll need R20 which is just over 3" thick. I just had Peter from VIP Foam spray a basement for me and the cost was roughly $1000 more after rebate than going with Roxul R20. it's very warm, I have to close all heating ducts and open the windows when I'm working there

20180119_175237.jpg
Good to know and thanks for the photo.

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