How to Attach a Ledger Board to Lap Siding
The manner in which lap siding covers the side of a house makes it impossible to connect a ledger board to. Ledger boards, which lend strength and support to a deck by connecting it to a house, must be installed on a virtually flat surface. The following steps will explain an easy method of removing the lap siding and attaching a ledger board.
Step 1 – Determine the Size of the Ledger Board
To ensure proper strength, a ledger board should be made out of the same size lumber that was used to make the deck joists (usually 2-inch by 10-inch boards). Measure the exact width and length of the ledger board with a tape measure. Next, snap a chalk-line across the siding the same length of the board. The chalk-line should be about 1-inch below the door that will open onto the finished deck. Using a 4-foot level, check to make sure the line is straight. If using a 2-inch by 10-inch ledger board, measure 10-inches below the first line and repeat the process; if using a different size ledger board, the distance between the first and second line should be the same as the width of the board. Use the level again on the second line to ensure it is straight. The edge of the level can be used to draw two vertical lines connecting the ends of the two horizontal lines to form a large rectangle shape. This is where the ledger board will go.
Step 2 – Use a Circular Saw
Set a circular saw to the depth of the siding. Cut along the outside edges of the chalk-lines that were placed on the siding. Once finished, use a hammer and chisel to pry the lap board off of the wall of the house leaving the sheathing beneath it exposed.
Step 3 – Cut Building Felt and Install Flashing
Cut two long strips of building felt long enough to span the distance of the opening cut into the siding. Use a staple gun to attach the felt at the bottom of the cut area first; then apply another strip of felt along the top of the area so that it overlaps the first piece by 3-inches. After the felt is stapled into place, carefully slide a piece of flashing behind the lap siding that rests directly above the top line that was cut. This flashing will not need to be secured with any fasteners, the pressure from the siding above should hold it, but it will need to be bent over the top of the ledger and around its corners in order to protect it from moisture damage.
Step 4 – Fasten the Ledger to the House
Lift the ledger into place and bend the flashing around it. Then, use zinc lag screws to secure the ledger board to the house. The screws should penetrate the ledger, the sheathing, the house and go into a framing beam such as a floor joist or a wall stud. Once the ledger board is tightly fastened into place, use a caulk gun to caulk all the seams between the ledger and the house with weatherproof caulk. This is the only way to ensure the connection is water tight.