Radiant in-slab heat insulation

[swandog]

Hi,

I have a radiant floor heat system in my basement slab. It is about 8 years old. Heat is from a mini-electric boiler. My basement is unfinished and is a walkout. My question is the insulation is not quite right...There is 2" insulation under the slab but nothing around the perimeter of the slab. I'm thinking about cutting into the slab around the foundation and then spray foaming in the gap. Do you think it is worth it to do this? By cutting I mean a diamond blade in my skil saw...so slow, dusty and loud

Thanks

Doug

[nobody05]

Thats sucks for you in alot of ways. #1 Electric Boiler the most inefficent way to heat a house. #2 insulation around the outside. It can be done but its going to be a labor intensive couple days. Yes it would work if you cut a couple inches down to the excisting foam and foam it shut again. Question would be is depending how wide your footing is that might be 6'' inside your basement wall.

[reddog]

Are you going to install a liner wall around the perimeter when you finish. Or strip the concrete wall? While edge protection would be nice. It's not the end of the world that you don't have it. It makes attaching carpet tack strip a pain.

[Tom7227]

Better buy a half dozen saws cause you'll need them. I think the project you are planing is way beyond a homeowners skill saw.

[MNice]

Keep in mind the slab is what provides lateral support for your foundation walls.

[MJBaldwin]

You would be better off putting in a small gas boiler and jacking up the heat will be cheaper and easier than cutting into that! Electric boilers arnt bad if you have them on off peak..

[minneman]

If there isnt insulation on the exterior of your foundation already, thats where it needs to be.

[Tom7227]

If there isnt insulation on the exterior of your foundation already, thats where it needs to be.

I agree. I would be willing to bet that the ratio of 'cold' that comes from the floor vs the walls is pretty steep.

Perhaps the problem in the basement is the lack of cold air returns. Most basements are cold because the systems aren't set up properly. Compounding the problem is a lack of a closed door between the upper floors and the basement, allowing all the cold air in the house to drop down. You can pump as much heat as you want into a basement but if there is nothing to stop it from going upstairs the basement will never feel consistently warm.

[swandog]

Thanks everyone for your replies. Yes it's an unfinished basement so no cold air returns and an open door to the upstairs. It would be a messy job and it's probably not worth it. The slab is free floating so no ties to the poured concrete walls...there is some insulation on the outside but it's the spray on kind and of marginal value imho. I may just cut in front of the patio door and spray foam into the crack.

Thanks

Doug