How to Build Wooden Decking Step by Step

A deck is one of the few big home projects a determined DIYer can genuinely pull off — and one of the few where a shortcut can literally collapse under a party. Learning how to build wooden decking comes down to getting the invisible parts right: the footings, the ledger connection, and the framing that carries the load. The pretty deck boards on top are the easy 20 percent. Spend your care on the structure below, follow local code, and you will build something that stands solid for 25 years instead of sagging in five.

Plan, Permit, and Call Before You Dig

Every deck starts on paper, not in the dirt. Sketch the size, height, and shape, and check your local building department — nearly all attached decks and any deck more than a foot or two off the ground require a permit and an inspection. This is not bureaucratic busywork; the inspector catches the framing errors that cause failures.

Before any digging, call 811 to have underground utilities marked, free of charge. Hitting a gas or electric line is a life-safety event, not an inconvenience. While planning, confirm your frost depth from the local code office, because footings must extend below it to prevent the deck from heaving in winter — often 36 to 48 inches in cold climates.

Choose Your Lumber

Wood choice sets your budget, lifespan, and maintenance load. All three common options work; they just trade cost for longevity.

• Pressure-treated pine: the standard, $2 to $5 per square foot of decking, rot-resistant and cheap but needs sealing every couple of years
• Cedar or redwood: naturally rot-resistant and beautiful, $5 to $9 per square foot, softer and still needs finish
• Tropical hardwoods like ipe: extremely durable and dense, $9 to $15-plus per square foot, harder to work

Regardless of decking, all framing lumber that touches the ground or stays wet — posts, beams, joists — should be pressure-treated and rated for ground contact. Use lumber labeled for the exposure it will face.

Step 1: Set the Ledger Board

For a deck attached to the house, the ledger is the most safety-critical connection in the whole project — a huge share of deck collapses trace back to a badly attached ledger. Bolt it to the house’s rim joist with proper structural lag screws or through-bolts on the schedule your code specifies, never with nails or deck screws.

Flash the ledger to keep water out of the wall. Slide metal or membrane flashing behind the siding and over the top of the ledger so water sheds away rather than rotting the framing behind it. Set the ledger height so the finished deck surface lands about an inch below the interior floor, keeping water and snow outside.

Step 2: Dig and Pour Footings

Footings transfer the deck’s weight into stable soil below the frost line. Mark post locations by squaring your layout with the 3-4-5 triangle method and running mason’s string. Dig each hole to the required depth and diameter — commonly 8 to 12 inches wide and below frost depth.

1. Dig each footing hole to code depth, keeping the bottom flat and undisturbed.
2. Set a cardboard form tube if required, and add a few inches of gravel for drainage.
3. Pour concrete and embed a galvanized post base anchor, checking it is level and aligned to your string lines.
4. Let the concrete cure at least 24 to 48 hours before loading it.

Post bases that hold the wood post above the concrete are worth the small extra cost — they keep the end grain out of standing water, the number-one cause of post rot.

Step 3: Install Posts and Beams

Stand your treated posts in the anchors and brace them plumb with temporary diagonal supports. Mark the beam height using a level line transferred from the ledger, accounting for a slight slope away from the house for drainage — roughly 1/8 inch per foot sheds water off the finished deck.

Cut the posts to height and set the beam. A built-up beam of two or three treated boards, or a solid beam, sits either on top of the posts (notched or on a post cap) or bolted to the sides. Post caps and heavy structural connectors from a maker like Simpson Strong-Tie give you code-approved, hurricane-rated connections — do not improvise these joints.

Step 4: Frame the Joists

Joists are the boards the decking screws into, and their spacing determines how solid the deck feels underfoot. Hang the outer rim joists first, then set the field joists into galvanized joist hangers along the ledger and beam.

Spacing matters and depends on your decking:

• 16 inches on center — the standard for most decking laid perpendicular to joists
• 12 inches on center — required when running boards diagonally, or for some composite and thinner boards

Nail every joist hanger with the specific structural nails the hanger calls for; drywall or deck screws are not rated for this and will shear. Check each joist crown-up (the slight bow facing the sky) so the deck settles flat, and add solid blocking between joists mid-span to stop bounce and twisting.

Step 5: Lay the Decking Boards

Now the satisfying part. Start along the house and work outward, or start at the outer edge — either way, keep boards straight with a chalk line reference. Leave a consistent gap between boards, about 1/8 to 1/4 inch, so water drains and the wood can expand; a common 16d nail or a spacing tool sets this evenly.

Fasten with either two coated deck screws per joist crossing or a hidden-fastener system that clips into grooved board edges for a clean, screw-free surface. Screws should sit flush or just below the surface, never proud enough to catch a bare foot. Let boards run long past the edge and cut them all flush in one pass at the end for a crisp line.

Tools and Materials You’ll Need

Gathering everything before you start saves a dozen trips to the store mid-project. Learning how to build wooden decking is as much about having the right fasteners on hand as it is about technique. Beyond your lumber, plan for the structural hardware and a solid tool kit.

• Structural hardware: galvanized or stainless joist hangers, post bases, post caps, and code-rated ledger fasteners
• Fasteners: exterior-rated deck screws or a hidden clip system, plus the correct structural nails for hangers
• Concrete: bagged mix and form tubes for the footings
• Layout tools: tape measure, chalk line, framing square, string line, and a good 4-foot level
• Power tools: circular saw, drill/driver, and ideally an impact driver for the hundreds of screws
• Safety gear: eye and ear protection, work gloves, and a dust mask when cutting treated lumber

Buy about 10 percent extra decking to account for cuts, waste, and the occasional warped board you set aside. Sight down every board before installing it and cull the badly bowed ones for short blocking pieces rather than fighting them into a run.

Avoid These Common Deck-Building Mistakes

Most deck failures and callbacks trace to a short list of avoidable errors, and knowing them upfront keeps your build safe and square. The single most dangerous mistake is a poorly attached ledger — nailing it instead of bolting it, or skipping the flashing that keeps water out of the house wall. Both cause the collapses and rot you read about.

Undersized or too-shallow footings that stop above the frost line are another classic error, letting the deck heave and shift each winter. Using the wrong fasteners — interior screws in joist hangers, or lag screws where through-bolts are required — creates connections that shear under load. And skimping on drainage details, like failing to slope the deck slightly away from the house or leaving no gap between boards, traps water and rots the surface early. Follow the code details, use the rated hardware, and let the inspector catch anything you missed. A permit inspection is free insurance on a structure your family will stand on.

Step 6: Add Railings, Stairs, and Finish

Any deck more than 30 inches above grade requires a guardrail by code, typically 36 inches tall for residential with balusters spaced so a 4-inch sphere cannot pass through. Bolt railing posts to the framing with through-bolts, not lag screws into end grain, for a rail that survives someone leaning on it.

Build stairs with consistent rise and run — often around a 7-inch rise and 11-inch tread — since uneven steps are a trip hazard the inspector will flag. Finally, protect your investment: seal or stain pressure-treated and cedar decks after they dry out, and re-coat every two to three years. A quality water-repellent finish is the difference between a deck that silvers gracefully and one that cracks and cups. Schedule your final inspection before you host that first cookout, and you will have built something that carries the crowd without a creak.