Installing step flashing without removing siding is possible as a repair method but requires careful technique to ensure watertightness, though removing siding is preferred for best results. If siding is already installed and you cannot remove it, you can install retrofit step flashing by carefully sliding new L-shaped flashing pieces behind the siding and interweaving with shingles. First, remove surrounding shingles along the wall using a flat pry bar to break sealant bonds and remove nails, exposing the deck. Then, use a thin pry bar or oscillating tool to gently create a small gap between siding and wall sheathing without damaging siding. Slide each piece of step flashing up behind the siding, with the vertical leg behind siding and horizontal leg on the roof deck, overlapping each piece below by at least 2 to 3 inches. Nail the flashing to the roof deck only, not the wall, to allow movement. Apply a small amount of polyurethane sealant behind the siding where flashing enters to prevent water entry, but do not rely solely on caulk. Reinstall shingles over each flashing piece, with each shingle covering flashing except lower edge. For vinyl siding, you can unlock panels to access. For hard siding like wood or fiber cement, you may need to cut a small channel. While this method works, it is not as reliable as removing siding to install flashing properly with house wrap overlap.
1 votes
Marked as accepted