How to Build a Deck

Building a deck is one of the most rewarding home projects, and it breaks down into four clear stages: set the footings, build the frame, lay the decking, and finish it. Work through the steps below — each has a calculator so you order the right amount — and tap “Add to my materials list” as you go to build one combined deck shopping list you can download or print.

DifficultyIntermediate–Advanced

Time2–4 weekends

Cost$$ (varies by size & material)

PermitsAlmost always required

Permits & safety: Decks nearly always need a permit and inspections — especially the ledger attachment and footings. Pull the permit before you build, and call 811 at least 2–3 business days before digging footings.

Build one shopping list as you go. Tap “Add to my materials list” on each calculator below and they combine into a single Deck list you can download or print.

View my list →

1Plan, lay out, and pull a permit

Decide the size, height, and where the deck attaches to the house. Check your local rules for railing and footing requirements, submit for a permit, and call 811 to locate utilities before any digging. A simple ground-level deck is far easier than a tall one with stairs.

2Set the footings

Dig footings below your local frost line and set posts in concrete. The footings carry the whole deck, so get them deep, plumb, and on solid ground. Use the calculator for how much concrete the post holes take.

3Build the frame

Bolt and flash the ledger to the house (the single most important detail — a bad ledger is the #1 cause of deck failures), set the beam on the posts, then hang the joists at 16" on-center. The calculator gives you joists, beam, ledger, posts, hangers, and fasteners.

4Lay the decking

Start straight off the house, gap the boards about 1/8" for drainage, land any end seams on a joist, and fasten with coated screws or hidden clips. The calculator returns boards and screws for your deck size and board choice.

5Stain and seal

Let pressure-treated boards dry out, clean the surface, then apply stain or sealer on a dry, mild day to protect against UV and water. The calculator sizes your stain and cleaner.

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Frequently asked questions

Do I need a permit to build a deck?

Almost always — most jurisdictions require a permit and inspections for the ledger and footings. Check with your local building department before you start; an un-permitted deck can cause problems at resale and may have to be rebuilt.

How deep do deck footings need to be?

Below your local frost line — often 30–48" in cold climates, as little as 12" in warm ones. Your building department publishes the local depth.

What's the most important part of a deck to get right?

The ledger connection to the house. It must be bolted (not just nailed) and flashed to keep water out — a failed ledger is the leading cause of deck collapses.

How much does it cost to build a deck?

It depends heavily on size and decking material. Add each step's calculator to your materials list and the list totals an estimated material cost for your exact deck — pressure-treated is cheapest, composite costs more up front but needs little upkeep.

Calculators in this project

Deck Framing

Joists, beam, posts and hangers for a deck frame.

Decking

How many deck boards and screws you need by deck size.

Deck Stain

Gallons of deck stain by deck size and coats.

Post-Hole Concrete

Bags of concrete to set fence or deck posts.

Gravel

How much gravel you need for a driveway, path, or base — in tons and cubic yards.

Fence

Posts, rails, pickets and concrete for a wood fence.