How to Add Flashing to Ledger Board
- 1). Determine where the ledger board will fasten to the house. Use a chalk line to snap a line to mark the location for the bottom of the ledger board. Measure up from that line to the top of the ledger board, adding 2 inches to accommodate the decking (if the decking is a standard 1-1/2 inches thick) and snap another line.
- 2). Use a power saw to cut along both chalks lines. Cut through the siding to the underlying framework. Use a pry bar and hammer to remove the siding between the two lines.
- 3). Pry the siding away from the wall area above the ledger board so you can slip the flashing into place. The flashing must be flush with the wall. Use a hammer to pry out any nails that prevent the flashing from being flush. If you can't get to the nails, slip a hacksaw blade under the siding to cut the nails.
- 4). Cut the flashing to the length of the ledger board.
- 5). Slip the 4-inch side of the flashing under the exterior siding.
- 6). Put the ledger board in place, flush to the bottom cut in the siding, and nail or screw it to the wall with appropriate fasteners.
- 7). Bring the bottom edge of the flashing down flush to the top of the ledger board with the 1-1/2 inch lip slipping down over the front of the board. That should leave 2 inches of flashing revealed above the ledger board.
- 8). Using No. 8 galvanized nails, nail through the siding and flashing into the exterior wall.
- 9). Attach the floor joists to the ledger board, with the top of the joists butting into the lip of the flashing.
- 10
Nail down the decking, butting the last board up against the house. That will cover the flashing, leaving about 1/2 inch of the flashing exposed above the decking. Any water that seeps up against the house will hit the flashing and be diverted below the deck.
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