how to extreme

Building a Code-Compliant Deck

Construction How-To, Decks, Decks, Outdoor Living July 13, 2015 Sonia


Support Posts

Deck support posts should be mechanically fastened both to the footing in the ground and the deck frame or beam. You want to ensure that your deck support posts resist lateral and uplift movement. Deck posts should be 4×6 pressure-treated lumber and have galvanized or stainless steel connectors attaching them to the rim joist.

Decks can be built with all sorts of designs. Here, we’re doubling up the rim of a small alcove before applying joist hangers. This small area was designed to store a gas grill.

Decks can be built with all sorts of designs. Here, we’re doubling up the rim of a small alcove before applying joist hangers. This small area was designed to store a gas grill.

If your posts are notched to hold a beam they should be a minimum of 6×6 (nominal) and have a corrosion-resistant post-to-footing and post-to-beam connector. There are a few retrofit options available to accomplish the post to beam. These connections are needed to resist lateral and uplift loads.

To guide our ¾” decking overhang, we temporarily face-nail a ¾” board around the rim to use as a gauge. Once installation is complete, remove the board and paint/stain the rim.

To guide our ¾” decking overhang, we temporarily face-nail a ¾” board around the rim to use as a gauge. Once installation is complete, remove the board and paint/stain the rim.

Adding diagonal bracing to both the parallel and perpendicular side of the deck post is also a good idea to reduce lateral motion and racking of the deck.  Diagonal braces should be installed at a 45-degree angles 24 in. down from the beam and 24 in. out from the post.

Joist Installation

Next, it’s time to install the joists. We start left to right and mark out the ledger and outside rim joist 16-inches on center in a square line.

We cut all our joists at the same time, toe-nail them to the ledger and direct-nail them through our single outside rim joist. Toe-nailing or direct nailing of joists is no longer an acceptable way to secure joists without additional support, so we add metal joist hangers afterward.

TIP: If the joist has a crown—a slight arc along its edge—install it crown-side up.

Joist Hangers

Joist hangers must meet IBC and IRC code of downward capacity. You can determine this by using an approved manufacturer’s product data based on the dimensions of your joists or header.

Use the recommended nails and fasteners for the metal connector you’re installing. Roofing nails, screws and box nails have no place in any metal connector system and should be avoided and replaced at all costs.

Also, make sure to install a properly sized nail or fastener into every metal connector hole provided.

Since we did not design a beam in this deck, the outside rim joist is then tripled, and is supported by the deck posts.