Basement insulation...

[arctic_scrap1]

I own a small house and I'd like to insulate the basement. I've heard that it is a bad idea to do though because the foundation will crack from not getting any of the house heat. Is there any truth to this? I'm just looking at 1.5" or 2" pink foam and 2x2 framing.

[MSRiverdog]

Didn't bother this guy.

http://www.thisoldhouse.com/toh/video/0,,20503345,00.html

[delcecchi]

I own a small house and I'd like to insulate the basement. I've heard that it is a bad idea to do though because the foundation will crack from not getting any of the house heat. Is there any truth to this? I'm just looking at 1.5" or 2" pink foam and 2x2 framing.

Many houses have insulated basements these days. I would say that is a bogus belief that insulating will wreck the foundation.

[StillwaterAaron]

Moisture control will be the biggest issue you will have. Just make sure you don't seal it up tight.

[MSRiverdog]

If he's not getting any water now it's not an issue.

[Tom7227]

I am not in the home improvement business but this issue seems to come up every year. My memory is that there are opinions all over the place but the one that counts is the one your building inspector has. At least that is what seems to be the answer when someone asks about putting up a stud wall and plastic and insulation. I appreciate that the OP didn't ask that and has a specific plan but I just wanted to throw that out there.

When I did my basement I put up 1x2 furring and insulation between those strips and then put a full 4x8 sheet of insulation over that. Covered it all with sheetrock. It seemed to me that there is little insulating value in a 2x2 and I wanted to break that barrier to my basement. Be sure to keep your sheetrock up a half inch or so from floor to be sure to cut off a route for moisture if the floor gets wet somehow.

[StillwaterAaron]

If he's not getting any water now it's not an issue.

Just because there is no water intrusion now does not mean that after changes there will be none. Condensation or seepage from the ground can both cause issues.

Tom has great advise.

[Surface Tension]

Sometimes when you take an old home and introduce new practices the results aren't favorable. Back filling is done differently now. Coatings are improved. Drain tile along interior and exterior of footings with a basin.

All of the above are IMO backups to what is the single most important issue when it comes to water and proven over again when we see new homes with water problems.

The water shouldn't be allowed to get there in the first place.

#1 Diverting water away from the house with landscaping. This is a year round solution as well. Come Spring all the ground is frozen except for the ground around the perimeter of your home. Guess where that water is going to run. If the backfill material allows that water to drain without resistance to the tile you might be OK. If you had a proper slope away from the foundation there wouldn't be water draining to the tile.

#2 Gutters and downspouts diverted away from the home. This is only a seasonal solution and not a substitute for landscaping.

Back to the question. If you insulate the exterior foundation to a 1' below grade there won't be any negative results. Along with that insulate the rim joist from the interior. Spray foam being best.

Accepted practice for insulation to the interior is closed cell foam tight to the foundation.