[Building4Me]

I'm working on my subfloor framing

and while installing rim joists I noticed 2 spots where I seem to have a 1/4-inch gap between the rim joist and the sill plate. The supporting concrete under is probably slightly lower in these spots. Do I need to shim them or should I even worry about it?

 

[Bud9051]

You need to close the gap to eliminate potential air leakage. As for support if the length of the gap is short not a problem. Be sure it is the concrete and not the rim joist. You want your wall above to be straight.

Bud

 

[Nealtw]

It may just be the crown in the joist and you would expect it to settle as you add the weight of the house above.

 

[Akcabin]

To me. Not all 2x? are the same width. Especially when you get to the wider ones 10-12" .I will have both rim n floor joists on the foundation. The 3/4" plywood TnG decking gets nailed down to cover both. You have to split the difference somehow. It works out in the end. You have to chase this till you get it right or it will haunt you. Slide a shim under it if you feel the need. I also prefer to have the rim joists spray urethaned 18" out from the rim. 8" thick. The vapor barrier one the walls is sealed on the top nicely.