The deck shown here cantilevers over a seawall in Channel Islands Harbor, Calif. Having built close to 30 others like it in this harbor, I’ve learned to incorporate details that accommodate movement in the deck framing, whether caused by the seawall or by the effects of weather on the materials used to build the deck. For example, instead of trying to make the heavy glass gate leading to the deck sag-proof, I designed it to be easily adjustable when inevitable structural- or weather-related movement occurs.
On the house side of the gate post, I attached a hold-down to the adjacent joist, using a 5/8-inch bolt through the post and hold-down (see photo and illustration, below). Below that, I ran one end of 3/4-inch-diameter all-thread adjusting rod through the post, securing it on the house side with a nut welded to a heavy-duty square washer, which in turn is attached to the post with an SDS locking screw. I ran the other end through a 4x8 bearing plate that rests on top of the seawall and is anchored to the bottoms of the joists, making sure the head of the rod was easily accessible below the deck. (For a deck without a plate, I could have installed a second hold-down on the joist for the end of the threaded rod.) Finally, I made sure the attachment point for the end of the threaded rod was solidly secured to the framing (I use either bolts or metal connectors and SDS screws here), so that when I adjust the threaded rod, all that moves is the post.