Build a Wooden Deck from the Ground Up

Building a deck is one of the most rewarding outdoor projects you can tackle. It's visible, it's functional, and when done right, it'll outlast most people's patience for home projects. The real work isn't complicated—it's methodical. You're essentially building a raised platform with careful attention to what holds it up. The difference between a deck that lasts 20 years and one that rots in five comes down to three things: how deep your posts go into the ground, how well water drains away from the wood, and whether you used pressure-treated lumber where it matters. This guide covers a ground-level to mid-height deck (up to four feet) on level ground. We're building to code, building it square, and building it to last. Larger decks, elevated decks, or decks on slopes require engineering and often a permit—that's a different conversation. If you're confident with a tape measure, a circular saw, and a power drill, you can do this.

1. Go Below the Frost Line. Mark post locations with spray paint, placing them no more than 8 feet apart along the rim and no more than 12 feet apart down the middle. Dig holes at least 3 feet deep in cold climates, 18 inches in mild ones—go below the frost line for your region. Make holes 10 inches in diameter for standard 6-by-6 posts.
2. Keep Posts Above Water. Place a 4-inch gravel bed in each hole, then set the post with a post-level or level tool held against two adjacent sides. Pour concrete around the post, slightly overmounded so water sheds away. Let concrete cure for 48 hours before building on it.
3. Seal Out Water First. If attaching to your house, bolt a pressure-treated rim joist ledger to the rim board or band board with half-inch bolts spaced 16 inches apart. Use flashing to keep water out from behind the ledger. If not attaching to the house, connect two rim joists between posts to form a rectangular perimeter, securing them with bolts and carriage bolts through the posts.
4. Level as You Go. Measure and cut pressure-treated 2-by-8 or 2-by-10 joists (depending on span) to length. Space them 16 inches on center running perpendicular to the rim joist. Secure each joist with two three-inch deck screws or carriage bolts at each end. Use joist hangers if you prefer—they're stronger than screws alone.
5. Stagger Joints Like Brick. Start at the house or one end with a full-width board, leaving a quarter-inch gap between boards for wood movement. Measure and cut each board at both ends before installation. Stagger end joints so they don't all line up in the same row—it weakens the deck and looks sloppy.
6. Space for Wood Movement. Use two three-inch deck screws per joist per board, driving them down at a slight angle so they're less visible. Pre-drill if you're using composite or hardwood; it prevents splits. Leave a quarter-inch gap between each board by using a spacer block or a nail as a guide.
7. Uniform Steps Save Ankles. If running boards around a post or tree, carefully mark and cut openings with a jigsaw. Leave at least a 6-inch gap between the wood and the post for air circulation. Build stairs using pressure-treated 2-by-12 stringers bolted to a blocking board at deck height, with pre-made stair treads or 2-by-10 boards fastened with deck screws.
8. Seal Within Two Weeks. Once all fasteners are set and trim is installed, sand the deck smooth with a floor sander rented from the hardware store. Apply a deck sealant rated for your climate within two weeks of construction. Reapply every 2 to 3 years to keep the wood from graying and splintering.