I'm trying to determine how to address a small gap between my foundation wall and the bottom of the house. I believe this gap is being used by vermin to access a crawlspace and travel up the walls.
What would be the best filler for this gap? I'm thinking perhaps caulk, but open to suggestions.
Best Answer
It looks like your siding is wood (probably cedar). You don't want to seal this too much - the underside of these shakes/shingles needs to be able to release moisture or your siding may rot sooner. Best option is to seal from the inside, probably with spray foam.
Edit based on comments: because you've indicated this is an inaccessible crawlspace, you should consider two other measures:
I'd encourage you to get access into your crawlspace and inspect there -- it's really the best way to ascertain the cause of your critter problems and enables the most effective solutions.