Gap parallel to sill plate on top of basement wall...

[abieniek]

Hi all - I am currently planning to spray foam the rim joists in my unfinished basement. This is all new to me, but I think I get how to do that. What I don't get is what to do with the space parallel to the sill plate. In pulling out old batting there was a good deal of mouse crap, so I need to seal up wherever they are getting in from the outside.

What do I do on the inside with this gap? Try to shove new batting in there? Seal the gap with spray foam? Something else? Hope I'm making sense. Maybe the picture helps...
https://drive.google.com/file/d/0Bysau8t9szMDUmlRNUpfSHE2UzQ/view?usp=sharing

 

[Jadziedzic]

How tall is the gap? You can pick up foam backer rods used for caulking in various widths (up to 3/4 in or wider) and jam those into the gap, assuming the gap is less than the maximum width backer rod you can find at the local home improvement store. Run a bead of caulk across the backer rod before the spray foam.

 

[Sponsor]

 

[abieniek]

How tall is the gap? You can pick up foam backer rods used for caulking in various widths (up to 3/4 in or wider) and jam those into the gap, assuming the gap is less than the maximum width backer rod you can find at the local home improvement store. Run a bead of caulk across the backer rod before the spray foam.

Yeah, so the gap is not huge. But I should seal the gap? It doesn't need to be open for any reason? I get scared about moisture issues and I don't want to create a new problem for myself.

 

[Jadziedzic]

Yes, seal the gap; that's a prime source of air infiltration into the house (and thus wasted energy). When the house was built a "sill gasket" should have been placed between the wood and the concrete in order to seal between the two, so there was already an attempt - albeit a poor one in many cases - to seal the gap.

 

[abieniek]

Thanks. Does it make a difference if I refill the space with batting or not? Is it worth the effort?