How to Frame a Deck
Hi, Jim Coshow here from Dunn Lumber. Today we're talking to professional deck builder Ron Spillers. Ron has been in the deck industry since 1985, and has constructed over 2,000 deck projects. We've partnered with Ron on a series of videos that cover frequently asked decking questions. In this post, Ron addresses what goes into framing a deck. For more in this series, click here. Here's Ron.
The Ledger Board
The first piece of framing that goes up is called a ledger board. It is the board that attaches the deck to the house. The ledger board is attached to the house using LedgerLOK Ledger Board Fasteners—designed specifically to secure the ledger board to the floor framing of the interior of the house.
Flashing
Just above the ledger board is the flashing. Flashing prevents water from getting behind the ledger board, which can cause serious challenges with rot and decay (if not done properly).
Deck Joists
The deck joists are attached to the ledger board with joist hangers. The hangers prevent the joist from dropping or wanting to pull away from the ledger board. Deck joists are spaced either 16" apart (called 16" on center), or in this case, 12" apart (12" on center) because the decking is turning on a diagonal and requires additional support.
An important thing to remember when attaching the deck joist to the ledger board is that pressure-treated lumber can vary in height (about ⅛"-¼"), so you don't want to put all the hangers in place and assume they'll all be level. It's better to attach the joist to the ledger via a toenail. This allows you to flush the top of each joist to the top of the ledger—and then you can attach your joist hangers after the fact. This best practice helps to get your joists as level as possible during this initial phase of construction.
If you are using manufactured decking, keep in mind that it will conform itself to any ups and downs in the deck framing. If you pick up one end of your deck joists and sight down the edges, you will see that most of them have a "crown" in them. You want to install your deck joists so that the crown faces up on all joists to avoid any humps in your finished deck surface.
Leveling
There are several ways to build the framework and get it level. At West Coast Decks, we build most of the framework on temporary supports. Then we hang our support posts, and pour the footings last.
If you choose to pour your footings first, you'll need to be very careful when leveling your deck. You can use transits levels, line levels, or four- to six-foot levels, and level as you go.
Treat End Cuts
We recommend always using pressure-treated lumber when framing your deck. Anytime you cut pressure-treated wood, you need to treat it again where it's been cut. This process keeps the inner, untreated wood from decaying (and keeps your warrantee intact).
Footings
Footings make a deck sturdy and strong. Most professionals dig and pour concrete footings, putting rebar into the bottom of the hole before the concrete is poured, and then the round Sonotube is added. You can use pier blocks in some jurisdictions—as long as they are on good, stable, and level ground.
We recommend digging 16" into the ground. Even though West Coast Decks use ground-contact treated lumber, we don't like the wood to contact the ground unless absolutely necessary.
All the metal framing connectors of the deck must be triple galvanized because treated lumber has a lot of copper in it, and regular steel will rust over time. (ZMAX® from Simpson Strong-Tie is a great example).
Picture Framing (or Bordering) the Deck
Picture framing, or bordering the decking, requires an additional joist and blocking. This particular blocking is to attach the rail posts to. This deck is being framed for an aluminum railing with surface-mounted posts.
The additional joist catches the deck boards as they come over, cut on a 45-degree angle, where they meet the picture frame board. Without the joist, the ends of the deck boards would be hanging in midair. There will also be joist blocking in between the joists, which adds stability to the frame. They sit on top of the beam and are cut to fit in between each set of joints.
Rim Joist
One of the last pieces that will go on the deck is the rim joist. We've run the deck joists out so they're cantilevered off the outer beam. The next step is cutting all the joists to have a straight, outer edge. The rim joists tie them all together.
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