Everything You Need to Know About Building a Deck
This woodworking DIY takes time and patience, but the final product is worth the work.
Facing a long summer at home? Transform your own backyard into a dreamy spot for everything from al fresco dining to late-night s'mores over a fire pit. And our favorite way to do that is with a new deck. You don't need to be a carpentry expert to update your outdoor space, says Geoff Case, pressure-treated lumber and decking merchant at The Home Depot, though some experience with tools and framing is helpful. "Building a deck is a job a DIY'er can tackle, but this should probably not be your first DIY project," he says. "If you are going to build your own deck, a ground-level platform is easier and a raised level platform is more challenging."
Understanding Local Codes
Before you begin any construction project, understanding your local codes and permitting requirements is essential. Since these vary from town to town, you should ask your township for a detailed list of the codes you need to follow—which can influence everything from the height of your deck and the depth of your footings to the type of railing you install and the number of stairs required. Expect your project to be inspected as you're building it—and to repair anything that doesn't pass before moving onto the next stage of your project.
Tools and Materials
Experts recommend using an online deck planner and materials estimator to create a design that fits your budget and lifestyle. "Pressure-treated lumber is the standard material to withstand weather; most pressure-treated lumber is wet when delivered directly from the store, so you'll need to let it dry before staining—typically for six months," says Hunter Macfarlane, a Lowe's project expert. "Composite decking is the ultimate in backyard decking—this wood-plastic hybrid is easy to maintain, resists scratching, is impervious to termites and decay and won't warp or splinter. It weathers lighter, so consider a deeper-hued initial purchase, but painting, staining, and sealing aren't required."
You'll also need to rent, buy, or borrow a variety of tools. "The most important tools you will need include a circular saw, carpenter square, chalk lines and reels, levels, a claw hammer, and screws," says Case. He also suggests an extension ladder, power drill, plumb bobs, post hole digger, wheelbarrow, and shovel—plus one other critical element: A partner. "A deck project will need the help of multiple people, as the task does have a substantial amount of lifting and cutting," he explains.
Framing the Deck
A sturdy 24-foot by 14-foot deck starts with 4-foot deep concrete footings for the side and corner vertical posts. "Use batter boards and mason's string lines to lay out locations for seven support footings of 12 inches in diameter," says Case. "The footings will help support the deck posts and provide the deck's foundation." You'll also need to secure a 2 by 12-inch board—called a ledger board—on your house at the height of your deck; different types of siding call for different installation methods, so check your local codes. Anchor 6 by 6-inch posts, check that they are square and level, brace them with diagonal supports, and cut the tops to the correct height. Next, install a 24-foot beam—made from two 2 by 12-inch deck boards—across the posts, and two 14-foot beams along the sides. "Be sure to diligently check beam alignment and adjust as necessary to make sure the beams are square," says Case.
The final framing step is installing the joists—the short pieces that run perpendicular to the house and support the decking. "Proper blocking between joists will help to build a stronger deck by allowing less movement over time," says Case. "The joist sizes and spacing depend on deck size, but the deck joists should never be spaced further apart than 16 inches on center." Use a framing square and level as you build to avoid ending up with an off-balance or out-of-square deck. "Get into the habit of checking each piece so your deck will remain level," says Case. "A level can also help plumb the posts of a deck: Use the leveler to measure vertically and horizontally to ensure your posts are plumbed correctly."
Finishing the Deck
Case recommends using self-drilling screws to attach the deck boards to the joists, since they are sturdier than nails and less likely to cause the boards to split. If you've chosen pressure-treated boards, which will shrink over time, install them with the sides of the boards touching; kiln-dried woods, like cedar and redwood, should be secured using nails as spacers, says Case. (Composite products come with their own hidden fasteners and spacers.) "When installing deck boards, it is important to keep each board spaced at the exact same distance," says Case. "It helps to use chalk to help keep the spacing accurate. Another tip on how to keep decking boards properly spaced is to start with a full board on the outside edge and then work towards the house or building—this will leave any odd boards less visible."
More complicated patterns require more work—installing the boards in an angled herringbone pattern means a lot more cutting and joists placed no farther apart than 12 inches—but give an elevated end result. "For larger decks, you can install parting boards—also called pattern boards—in the middle of the decking," says Macfarlane. "These decking boards run perpendicular to the rest of the decking, creating an eye-catching design. They also allow you to use shorter deck boards and can eliminate the need to butt boards together to span the width of the deck."
The final steps include installing railings and a staircase (with footings). Planning the timeline for your DIY deck build depends on everything from the size of your space and your terrain to your woodworking experience and the weather, but with patience, focus, and attention to detail, you can DIY an outdoor space that's as meditative to build as it is to use. "The best aspect of a deck project is that it takes place outdoors," says Case. "This allows the builder to step away from the project when they need a break."
How to Repair a Deck
If your property includes a deck that's seen better days, your summer to-do list may only include repairing a few sections instead of building a completely new one. "Decks that are exposed to harsh weather elements tend to become damaged more quickly," says Case. "However, regular inspections can spot issues ahead of time. Most damage results in rotted wood, loose boards or nails/screws sticking up." Pry up loose or damaged boards and inspect the joists for signs of rot; dig out damaged wood from the joists, fill in the gaps with wood putty, and reinforce the joist by installing a second, brand-new joist against it. Then you can replace splintered or decaying deck boards using the same process you'd use for a new deck: Set the spacing and secure with screws. "If rot or water damage is showing in every single board, then it would be necessary to replace the entire deck," says Case. "However, most of the time, you will only need to replace a few boards at a time."