Build Your First Deck: A Step-by-Step Guide

1 Plan your deck size and location

Start with a sketch. Measure the area where the deck will go and mark it on graph paper or in a notes app. A typical first deck is 12×16 ft — large enough for a table and chairs, small enough to manage as a solo or two-person project.

Think about traffic flow: will you access the deck from a door? Where will stairs go? Account for clearance from property lines — most jurisdictions require 5–10 ft setbacks, but check your local zoning rules.

2 Check permit requirements and underground utilities

Before digging a single hole, do two things: call 811 (the national "call before you dig" service) to have underground utilities marked, and contact your local building department about permits.

Most jurisdictions require a permit for a deck attached to the house or elevated more than 30 inches above grade. The permit process typically involves submitting a drawing with dimensions, footing locations, and framing details. Our permit guide explains what to expect.

Don't skip the permit. Unpermitted decks can create liability issues, complicate home sales, and may not be covered by homeowner's insurance if they cause injury.

3 Lay out the footing locations

Footings are the concrete anchors that transfer the deck's weight to the ground. For a freestanding deck, you need footings at all four corners and along the perimeter at no more than 8 ft intervals. For an attached deck, the ledger board (attached to the house) replaces one row of footings.

Use batter boards and string lines to lay out the footing positions accurately. Squareness matters — the "3-4-5 rule" is your friend: if one side is 3 ft, another is 4 ft, and the diagonal is 5 ft, the corner is square.

Footing depth must extend below your local frost line — this varies from 12 inches in the deep South to 48+ inches in Minnesota. Your building department will specify the required depth for your area.

4 Dig and pour the footings

Dig footing holes with a manual post hole digger or rented power auger. The hole should be about 12–16 inches in diameter and deep enough to reach below the frost line.

Add 6 inches of gravel to the bottom of each hole for drainage. Mix and pour concrete according to the bag directions, then set post bases or tube forms according to your plan. Let concrete cure for at least 48 hours — ideally 7 days — before loading it.

Standard rule of thumb: 2 bags of 80 lb concrete per footing for a typical residential deck. The deck calculator computes this automatically.

5 Install the ledger board (attached decks only)

If your deck attaches to the house, the ledger board is the most structurally critical connection. It carries half the deck's load and must be properly flashed to prevent water from getting behind it and rotting the house rim joist.

Remove siding in the ledger area. Apply self-adhering flashing tape, then lag-bolt the ledger through the house sheathing and into the rim joist. Use approved hardware — the IRC specifies lag screw size, length, and pattern for ledger connections. Your local code may require an inspection at this point.

Never skip flashing. Water behind a ledger is one of the most common causes of deck structural failure.

6 Frame the deck

Framing consists of: the beam (supported by posts on footings), the rim joists (the outer perimeter), and the interior joists (spaced 12–16 inches on center). Use pressure-treated lumber rated for ground contact (UC4B) for any wood that contacts or is near the ground.

Joists hang from the beam and ledger using metal joist hangers — never toe-nail load-bearing connections. Joists are typically 2×8 or 2×10 lumber, spaced 16 inches on center for most decking products.

The deck calculator outputs joist count and total framing linear footage. Print that list before visiting the lumberyard — framing lumber is sold by linear foot.

7 Lay the decking boards

Start from the house and work outward, or from one end. For wood decking, use two 2.5" or 3" deck screws per board at each joist crossing. Pre-drilling near board ends prevents splitting. Leave a 1/8" gap between boards (use a spacer — a 16d nail works well) for drainage and expansion.

For composite decking, follow the manufacturer's instructions exactly. Most use hidden fastener clips that slide between boards at every joist. Gap spacing and clip installation vary by brand.

Run the last board slightly long and snap a chalk line to cut all boards flush in one pass. This gives a cleaner edge than trying to cut each board perfectly before install.

8 Install stairs and railings

If the deck is 30 inches or more above grade, the IRC requires guardrails (railings). Standard residential railing height is 36 inches; some local codes require 42 inches. Balusters must be spaced so a 4-inch sphere cannot pass through any opening.

For stairs: measure the total rise (ground to deck surface), then use the stair calculator to get your riser count, tread count, and stringer length. The calculator also flags any IRC violations (riser height over 7.75") and recommends a fix.

Use the railing calculator to determine post spacing, baluster count, and exact gap — it enforces the 4-inch sphere rule automatically.

9 Finish and maintain

For pressure-treated wood decks: let the lumber dry for 60–90 days before applying stain or sealer. New PT lumber is wet from the treatment process. Apply a quality deck stain every 2–3 years to protect the wood from UV and moisture.

For composite decks: no stain or sealer needed. Clean annually with a composite-safe cleaner and a soft brush. Avoid pressure washing above 1500 PSI — it can damage the board surface.

Inspect your deck every spring: look for loose fasteners, soft spots, rotting wood, and wobbly railing posts. Deck failures most often occur at connections — ledger bolts, post bases, and stair stringers.