Foundation/sill plate coating
I have an exterior foundation/sill plate finishing question. 100 year old shingle-style house, 2 storeys with no basement in Pacific Northwest. The cement foundation is solid, no water penetration issues but low to the ground, ie. normally I believe there’s a 6” gap between the grade and bottom of the siding, but I’ve less than that and in some cases no gap due to a slight slope to the lot. I have hardie board siding on top of wood sheathing (?) and at the bottom of the siding is a 2 x 6 vertical board (‘base board’) with metal flashing running on top of it (below the last course of siding over the top of the base board). Please see first picture for clarity. I can pull the base board off (pictures 2 - 4) and apply a coating or material from the bottom of the flashing over the old sheathing, sill plate and down to the foundation, then re-attach the base board.
What kind of material should I use to cover the space between the top of grade to the bottom of the siding? Needs to cover the cement foundation, wood sill plate and wood siding up to the bottom of the hardie board siding.
I’ve read about various possible coatings including parging, spray-foam, caulking, Blue Skin, Blue Seal. I’m mainly trying to prevent bugs, rot, rodents and cold air from penetrating the space.
Any advice is greatly appreciated. Thank you.