How to Install a Deck Ledger Board

What You'll Need
Galvanized metal "Z" flashing
Measuring tapes
2-by-10 treated lumber
16 Penny nails
Caulking guns
Chalk line
Circular saws
Lag mult-iuse screws
Pry bars
Safety goggles
Silicone caulks
Variable-speed drills
Safety goggles

The ledger board is one of the most critical parts of your new deck. It attaches to the house and acts as the main support for the part of the deck that you walk out onto from your door as well as a reference point for laying out the remainder of your deck area. Because the ledger board is so crucial to creating a structurally sound deck, you must ensure that the ledger board is positioned properly and securely attached to the house. Therefore, here is a step-by-step guide to help you correctly install the ledger board for your new deck:

Step 1 – Measuring and marking

Mark the position at the top of your deck against the existing siding of your home. This should be about 1 to 2 inches below the interior door seal. You do not want to allow for too much distance as water, ice or snow may build up and leak into the door seal.

Step 2 - More Measuring

Draw a line that indicates the full length of your new deck. Make sure to allow for the combined thicknesses of the decking board as well as the width of the ledger board that will be attached to your exterior wall. For our example, we are using 2-by-10 pieces of treated lumber for our ledger board. Therefore, we would need to measure 1-1/2 inches for the deck boards and an additional 9-1/2 inches for the ledger board which would be 11 inches total. Next, use a chalk line to create a straight line between the two major points.

Step 3 - Remove Siding

Use your circular saw to cut along the lines you drew and cut out the siding from the house. Make sure to set the thickness of your blade to just enough to cut only the siding. Then use hammers or a pry bar to remove the siding from your house between the two marked lines.

Step 4 - Aligning the Ledger Board

Place the ledger board so that the lower edge of the ledger board is properly aligned with the lower edge of the cut siding. You can use a couple of 16 penny nails that are partially driven in to hold the ledger board in place. These nails are temporary, so make sure not to drive them in all the way.

Step 5 - Drilling Holes

Pre-drill holes through the ledger board into the side of the house for your lag screws that will be inserted later.

Step 6 - Remove the Ledger Board

Remove the ledger board from the house then and squeeze and apply silicone caulk into each pre-drilled hole. The silicone will act as a moisture seal for the areas where lag bolts are inserted.

Step 7 - Attach the Ledger Board

Place the ledger board back into the cutout area of the house and use lag screws to attach the board securely to the side of the home. Make sure that the lag screws are tightened very tight, thus securing the ledger board.

Step 8 - Adding More Silicone

Use your caulk gun to run a large bead of silicone over the top of the ledger board.

Step 9 - Install Flashing

Use the galvanized flashing under the exposed siding and over the top of the ledger board to help prevent water from seeping in between the house and the ledger board.

Step 10 - Caulking and Finishing Up

After you install the flashing, fill in any gaps or crevices with silicone caulking. Once the silicone dries and you're satisfied that the ledger board won't leak and is securely fastened, you can continue with the other steps in building your deck.