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I need to add a porch to an existing house where the new porch floor and the old floor are to be in roughly the same plane. The old floor rests on the typical plywood subfloor which rests on floor joists/rim joists, which, in turn, rests on a poured concrete basement wall. If the new floor is to be within a few inches, or less, of the old floor of the existing house the new floor will butt to the rim joist of the old floor. If the new porch floor is poured concrete, is there anyway of attaching the new to the old floor without running into water and termite problems where they join? Also what’s the best way to physically tie the new and old foundations together to avoid separate movements from freezing and drying of the soil?
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I need to add a porch to an existing house where the new porch floor and the old floor are to be in roughly the same plane. The old floor rests on the typical plywood subfloor which rests on floor joists/rim joists, which, in turn, rests on a poured concrete basement wall. If the new floor is to be within a few inches, or less, of the old floor of the existing house the new floor will butt to the rim joist of the old floor. If the new porch floor is poured concrete, is there anyway of attaching the new to the old floor without running into water and termite problems where they join? Also what's the best way to physically tie the new and old foundations together to avoid separate movements from freezing and drying of the soil?