Insulating under a small Bay Window
I live in upstate NY and have a West-facing bay window that is always cold in the winter. The windows are good quality and insulated/caluked well. The floor and near the baseboard actually has a draft in high winds. I can access the joists going out the the bay from the basement. They currently have fiberglass batting stuff in as far as possible and the underside of the bay from outside is simple plywood with some caulk around the perimter.
My thought - remove the fiberglass batting and spray foam the entire space from the basement. And also re-caulk the exterior underneath.
My question - this is an area about 24" deep, 5' wide and 12" high. Is there a product a homeowner can use to fill this space? It seems to small to call in an insulating company, but too big for the spray foam cans...