How to Repair a Collapsed Deck Ledger Board

Remove any remnants of the collapsed ledger board from the house rim joist. The ledger is held fast to the building by bolts or nails and will require some unscrewing with a wrench or some prying with a crowbar to get it loose. Discard the old board and inspect the rim joist for damage or rot. If the wooden elements within the house structure are sound, they can be reused as the anchor point. If not, they have to be replaced just as they are.

Install a sheet of paper flashing onto the joist to repel water and prevent rot. Measure the size of the old ledger board and use your circular saw to cut a piece of 2-by-8 pressure-treated lumber to match. Place the new ledger against the side of the house, and use your power drill to make pilot holes through it and into the joist behind. Make sure none of your pilot holes are in the same places as the previous ledger installation.

Instal 1/2-inch galvanized lag bolts and washers into the pilot holes. Use your impact wrench to do the tightening and place one bolt every 16 inches or so in a staggered (up and down) pattern so as not to create any weak seams in the wood. With the ledger in place, your deck can be reattached using whatever system of brackets, blocking or braces employed in the original construction process.