DIY Build a Freestanding Cantilevered Deck

By Matt Weber

Build a Freestanding Cantilevered Deck Support by Parallel Beams.

Around Alabama, where EHT is headquartered, most decks are connected to the side of a house with a ledger board fastened to the rim joist of the house. When done correctly, this is a strong and code-compliant method of building. But, when flashed or fastened incorrectly, this connection can pose potential problems, such as providing a prime location for water to collect against the house wall and ledger board, ultimately contributing to rot.

As an alternative to the ledger, the deck I recently built is a freestanding structure, basically a giant platform built right next to, but not connected to, the house wall. The house in question had two stories with a finished basement on the bottom level. The finished ceiling of the basement prevented access to the interior side of the rim joist. Unless I was to tear out the ceiling, I wouldn’t be able to add nuts and washers to through-bolts on the interior side of the rim joist. And, if I couldn’t fasten the ledger with through-bolts, then I’d have to use lag screws. Although some heavy-duty lag screws are strong enough to attach ledgers to rim joists, if the wood were to eventually rot, then no matter how strong the lag screws, they could potentially pull out of the rotted wood. So, I figured that by building a freestanding deck, I could avoid these potential hazards altogether.