The house was built in 1930 and besides some bays stuffed with fiberglass the basement is uninsulated and unfinished. After two MN winters in the house I've managed to fill the larger holes but have found that a lot of air still comes in between the block and rim joist.

Will spraying the rim joist area, which contains no sill plate, with closed cell spray foam be likely to lead to moister issues since the wood rests directly** on the block? The basement does get humid in the spring/summer but a small dehumidifier easily takes care of it. The wood without fiberglass remains dry year round.

** "Directly" because there are areas that don't touch and other areas that seem to have a bit of tar paper underneath.

The house is stucco and from the inside out goes Wood Joist >> 1x8 Cladding >> Stucco.

Finally I did see these two posts but both refer to wood that is much more encased in concrete:

No sill plate - orange foam is attempt to seal larger air entry point.

Much of the rim joist area has sloped concrete sitting on top of tar paper, though it isn't really attached permanently. Much of the rim joist area has concrete.

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