Step 1: Check local codes and get a permit

• Call your city or county building department before you buy anything.
• Ask about setbacks from property lines, height limits, guard (railing) rules and the required footing depth.
• Ask which inspections they want during the build. Many want to see the footing holes before concrete goes in.

Step 2: Design your deck

• Measure the wall where the deck will attach and decide the size, shape and height.
• Think about sun, wind, privacy and where the door swings.
• Draw a simple sketch with dimensions: ledger, beam, post locations and joist direction.
• Joist size, beam size and post spacing all depend on your spans. Your permit plans and local span tables set them.

Tip: Bring your sketch to either store. We'll help check spans and build the full material list with you.

Step 3: Call 811 before you dig

• Call 811 to have underground utilities marked. It's free.
• Wait the required time (usually 2–3 business days) before digging.

Step 4: Lay out the deck

• Snap a chalk line on the house where the top of the ledger will sit.
• Outline the deck with stakes and string.
• Measure both diagonals. When they match, the layout is square.
• Mark footing locations from your plan.

Step 5: Install the ledger board

• Remove the siding where the ledger goes. A ledger should never be fastened over siding.
• Flash the wall and the top of the ledger so water can't get behind it.
• Fasten the treated ledger into the house rim joist with ledger-rated structural screws or bolts.
• Fastener size and spacing come from your local code and depend on joist span. Follow the screw maker's chart.

Most important step: Most deck failures happen at the ledger. Don't use nails, and don't skip the flashing.

Shop this step: Structural screws · Flashing tape · Treated lumber

Step 6: Dig the footing holes

• Dig below your local frost line. Your building department sets the depth, and in our part of the country it's deep.
• Make holes wide enough for the footing size on your plan, and clear out loose soil.
• Schedule the footing inspection now if your town requires one.

Step 7: Pour footings and set posts

• Add a few inches of gravel to each hole for drainage.
• Pour concrete and set an elevated (standoff) galvanized post base in each footing while it's wet. It holds the post just above the concrete so the end stays dry.
• Finish the top of the concrete slightly above the ground and slope it so water runs off.
• Let the concrete cure (see the bag; usually 24–48 hours) before loading it.
• Stand posts in the bases, plumb them on two sides, and brace them.

Shop this step: Concrete mix · Post bases

Step 8: Cut posts to height

• Mark every post level with the ledger using a line level or laser.
• Measure down from that mark by the beam depth plus the joist depth (for a beam that the joists sit on). A double 2x10 beam is 9¼ in. deep, not 1½ in.
• Cut square and clean.

Step 9: Build and set the beam

• Build the beam from two or three treated boards (size from your plan), fastened together and crowned up.
• Set it on the posts and fasten it with post cap connectors.
• Check that it's level end to end.

Shop this step: Post caps

Step 10: Hang the joists

• Mark joist spacing on the ledger (usually 16 in. on center; some composite boards and diagonal layouts need 12 in.).
• Install joist hangers on the ledger with the nails the hanger maker specifies. Ordinary deck screws aren't rated for hangers.
• Set each joist in its hanger and across the beam. Keep the crowns up.
• Secure joists to the beam with hurricane ties or the connector your plan calls for.

Shop this step: Joist hangers · Joist hanger nails

Step 11: Add the rim joist and blocking

• Fasten a rim joist across the outer ends of the joists. It runs parallel to the ledger.
• Add blocking between joists at mid-span to keep them straight.
• Check the frame for square one more time before decking.

Step 12: Install the deck boards

• Start with a straight board along the house, leaving a small gap at the wall for drainage.
• Fasten with two screws at every joist. Pre-drill near board ends to prevent splitting.
• Gap boards evenly (typically ⅛–¼ in. for wood; follow the maker's spacing for composite).
• Stagger butt joints, and land every joint on a joist.

Shop this step: Decking · Deck screws

Step 13: Trim the edge

• Let boards run long, then snap a chalk line and cut them all at once with a circular saw.
• Ease rough edges with sandpaper.

Step 14: Install railing posts

• Space posts per your railing system or plan.
• Bolt posts to the rim joist with added blocking or post-to-joist hardware. Avoid notching posts; it weakens them.
• Make sure every post is plumb and the same height.

Step 15: Install rails and balusters

• Cut top and bottom rails to fit between posts. Set the bottom rail a few inches above the deck.
• Cut balusters and space them so no gap is 4 in. or more.
• Optional: add a 2x6 cap rail across the top for a finished look and a place to set a drink.

Shop this step: Railing kits

Step 16: Figure the stair layout

• Measure the total rise from the landing spot to the top of the deck.
• Divide it into equal steps. Under the IRC, used by most towns, each riser can be no more than 7¾ in. and each tread at least 10 in. deep.
• Plan a solid landing at the bottom: a concrete pad or compacted gravel.

Step 17: Cut and set the stringers

• Lay out one stringer on a treated 2x12 with a framing square, cut it, and test the fit.
• Use it as the pattern for the rest, or start from precut treated stringers.
• Attach stringers to the deck frame with hangers or brackets and rest them on the landing.

Shop this step: Stair stringers

Step 18: Install treads

• Fasten treads to every stringer and check each one for level.
• Add risers if you want a closed look.
• Add a graspable handrail if your stairs have four or more risers (check local code).

Step 19: Sand and clean

• Sand splinters, especially on rails and stair treads.
• Sweep off sawdust and debris.

Step 20: Stain or seal

• New treated lumber often needs to dry out before it takes stain. Sprinkle water on it: if it beads, wait.
• Apply in the shade, following the can's directions and dry times.

Shop this step: Deck stain

Step 21: Final inspection

• Schedule your final inspection.
• Recheck every connection, railing and stair for tightness.

Step 22: Keep it in shape

• Inspect connections, boards and railings every spring.
• Clean the surface and reapply stain or sealer every 2–3 years.
• Replace soft or cracked boards right away.