Deck Building Ledger

The Deck Ledger Board Plays a Critical Role in the Connection of the Deck to the Home

By Mark J. Donovan

The deck ledger board plays a major role in deck construction. It is in essence, the interface between the deck itself and the home. The deck ledger board connects your deck to your home.

It typically consists of either a pressure treated 2×8 or 2×10, depending upon the size of the deck and the size deck floor joists you plan to use.

It is critical when selecting the lumber for the deck ledger board to be as straight as an arrow. 

It should be checked to ensure that it is not warped or twisted in any way. To do this, just lift up one end of the prospective ledger board to your eye, like you were sighting a gun, and look down the length of it.

Rotate it slowly on all four sides. As you do, inspect for any bows or twisting in the lumber. Also inspect the prospective lumber for splits, cracks, and ingrown knots. Most building lumber contains some knots, however for the deck ledger board it should be limited to very small knots. In addition, try to select a piece of lumber for your deck building ledger that comes from near the center of the tree, versus the outer edges. You can tell this by looking at the grain of the lumber on one end of it.

If you observe the grain to have a significant curve in it then it is from the outer edge of the tree. This type of lumber is known as flat grain lumber.

If you observe a piece of lumber that has small center circles in it then you know it has come from the center of the tree.

This type of lumber is known as vertical grain lumber and is consider the most stable and is less prone to warping and twisting.

 Siding saver mounting brackets attached to deck ledger board.

After finding the perfect piece of lumber for your deck ledger board, the next step is installing it onto the side of your home. It should be positioned at a height that will represent the desired deck height. Keep in mind that the decking lumber will add another approximate inch to the height of the deck.

Also, it is imperative that the finished height of the deck be located at least one foot step down (7 to 8 inches) from the threshold opening of the house door to the deck. This is necessary to prevent rain water from draining and backing into the home.

The deck building ledger should be fastened directly to the exterior house sheathing, versus over the house siding, unless you plan to use siding saver mounting brackets.

Consequently, unless using the siding saver mounting brackets, you’ll need to remove a sufficient amount of the exterior house siding to install the ledger board.

In addition, when installing the deck ledger board to the exterior house sheathing first apply ice and water shield to the exterior sheathing area prior to attaching the ledger board to it.

Deck Installation Bid Sheet

The deck ledger board should be fastened to the side of the home using non-corrosive lag bolts or carriage bolts that penetrate deeply into or through the house sill plate, respectively. A bolt should be installed into the deck ledger board every 16 inches for maximum strength.

Also, make sure to use a spirit level to ensure that the ledger board is attached level to the side of the home. Again, the deck building ledger connects the deck to the home and thus it needs to be securely fastened into place.

After attaching the deck ledger board to the exterior house sheathing, run a bead of silicone caulk along the seam where the ledger board meets the home.

Then install deck flashing over the ledger board and up the exterior house sheathing a few inches.

The silicone caulk and deck flashing will ensure no water penetrates behind the ledger board.

With the deck building ledger board solidly mounted to the home, you can then move forward with the installation of the rest of the deck framing members, including the outer and inner joists and end beam. Next, you can install the decking boards and railings.

Finally, you can reinstall the exterior house siding near the deck building ledger board to wrap up the project.

For help on building a deck, see’s Deck Installation Bid Sheet. The Deck Installation Bid Sheet will teach your how to hire the right deck contractor, and help to ensure that your deck project is completed on time and budget.

Deck Installation Bid Sheet

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