Mark the corners of the deck with stakes and square the outline by measuring with a tape measure from corner to corner and moving stakes until those diagonals are identical. Mark locations for any interior posts with stakes. Place posts at least every 8 feet.
Dig holes with a post-hole digger or auger for 4-by-4-inch posts. Excavate dirt below the line where the earth freezes and about a third the depth of the finished post, 4 feet for a post with footings on a 3-foot-high deck with a railing around it. Make holes at least 8 inches in diameter. Put 6 to 8 inches of gravel in the bottom of the hole and compact it with a hand tamper. Pour a concrete footing of equal depth as an alternative.
Set poles in the holes, brace them with gravel at the bottom and plumb them on all sides with a level. Double check spacing with a tape measure to make sure 8-foot beams fit exactly between them and the outline remains square. Fill the holes around the posts with concrete, slightly above ground level and tapered away from the posts.
Place 2-by-6-inch beams around the outside of the posts, set level at 3 feet high. Use a level to get the boards level and fasten them to the posts with 3-inch galvanized screws. Cut boards on two sides with a circular saw 3 inches short, to fit between the boards on the other two sides. Screw the ends of those boards together. Put longer boards on the long sides of a rectangular deck.
Install 2-by-6-inch joists between the outer beams, using metal joist hangers, U-shaped brackets fastened on the insides of beams to hold the joists. Secure hangers with 2-inch galvanized screws and a screw gun. Run the joists across the narrow width of a rectangular deck. Level the tops with the tops of the outside beam.
Fasten 1- or 2-inch flooring boards to the joists and outer bands; use deck boards, 1 by 5 1/2-inches or 2-by-6-inch boards. Screw these to the outer bands and joists with 2 1/2-inch galvanized deck screws. Cut board ends with a circular saw to fit around vertical posts.
Make a railing of 2-by-4-inch top and bottom rails with 2-by-2 or 2-by-4 vertical spindles between them. Fasten spindles to rails with galvanized screws and railings to posts with screws, driven diagonally through the horizontal members into the posts. Place steps at an opening. Buy pre-cut stringers with at least 3 steps and nail or screw them to the outer beams, then cover them with tread boards.
Things You Will Need
- Tape measure
- Post-hole digger or auger
- 2-by-6-inch lumber
- 3-inch galvanized screws
- Screw gun
- Metal joist holders
- 2-inch galvanized screws
- Deck flooring, 1-by-5 1/2-inches or 2-by-6
- 2-by-4-inch railing boards
- 2-by-2-inch or 2-by-4-inch rail spindles
- Pre-cut stair risers
- Stair boards
- Use pre-cast concrete piers with metal post holders set in them as an alternative to digging post holes.
- Fasten one end of a 3-foot deck to a house wall with a 2-by-6-inch ledger board secured to wall rim joists or other framing with lag bolts. Use the ledger to replace one side of deck posts.