Insulating Sill Plate

Atskodinski · 12-17-2010, 11:17 AM

Going to be insulating around the perimeter of my basement between the sill plate and the foundation. Curious which would work better here, caulking or expanding foam?

I'm using rigid foam in the rim joists with expanding foam to fill in the gaps around the sides.

AndrewF · 12-17-2010, 03:18 PM

expanding foam will give a better seal.

Atskodinski · 12-17-2010, 03:59 PM

Thanks. Was leaning that direction but was curious to see others experience.

AndrewF · 12-17-2010, 04:16 PM

I personally did spray foam on mine. I have around 70 "boxes" and wasnt about to cut foam board for each one and then try to get a caulking gun in there.

**Gary in WA** · 12-17-2010, 07:08 PM

If in a high problem insect area, use caulking as they eat or go through foam. Use rigid foam on top the plate also.

Gary

Atskodinski · 12-17-2010, 08:52 PM

Quote:

Originally Posted by GBR in WA

If in a high problem insect area, use caulking as they eat or go through foam. Use rigid foam on top the plate also.

Gary

I plan to use rigid foam on the top plate. I'm just going to foam the small gap between the bottom plate and the top of the foundation.

**Gary in WA** · 12-17-2010, 09:16 PM

If no sill sealer there, use either-or. Some bugs go through foam after crawling under the p.t. sill plate because the concrete sub never rodded (scrapped smooth) the top of the wall after pulling the forms.Or they "hand" troweled the wet concrete rather than using a float tool. Or the p.t. plate dried out and cupped and bowed up between the required spacing of the fasteners. The moisture will still come through as long as contact is made without a sill sealer: http://www.greenbuildingadvisor.com/...-building-code

Gary

Atskodinski · 12-18-2010, 12:48 AM

Quote:

Originally Posted by GBR in WA

If no sill sealer there, use either-or. Some bugs go through foam after crawling under the p.t. sill plate because the concrete sub never rodded (scrapped smooth) the top of the wall after pulling the forms.Or they "hand" troweled the wet concrete rather than using a float tool. Or the p.t. plate dried out and cupped and bowed up between the required spacing of the fasteners. The moisture will still come through as long as contact is made without a sill sealer: http://www.greenbuildingadvisor.com/...-building-code

Gary

Thanks for link. Haven't checked it out, but will. No sealer on the sill. House built in '56. Not that well maintained either which puts me in a continuous state of DIY projects. Upon further review, I'm not even sure the gap between sill and block foundation is wide enough to make foam a good option. Think I'm just going to fill the big gaps with scraps of rigid foam and caulk the perimeter, but will use foam around the rigid foam I'm putting in the box. Understand the insect conern though.