Deck Materials List: Boards, Joists and Screws for a 12×16 Deck
The surface of a 12 × 16 ft deck takes 29 deck boards of 16 ft (39 of 12 ft if you prefer shorter boards), 13 joists, about 676 screws, and 1 gallon of stain for one coat. This list covers the decking and joists, which can be counted from the size. The posts, beams, footings and ledger depend on your plans and local code, so they are listed at the end for you to fill in.
The materials list (surface and joists)
| What to buy | How much | How we worked it out |
|---|---|---|
| Deck boards (5½ in) | 29 boards of 16 ft | Deck board calculator: 26 rows across the 12 ft width with 1/8 in gaps, 10% waste. In 12 ft boards: 39 |
| Joists | 13 joists, 12 ft long | At 16 in on center along the 16 ft length. Joist size is set by the span, the wood and your building code |
| Deck screws | About 676 | Two for each board at every joist. Use screws rated for exterior and treated lumber |
| Joist tape | 156 ft | Self-adhesive flashing on the top of each joist, to protect the wood from the water that gets between boards |
| Joist hangers | Up to 26 | One for every joist end that hangs from a ledger or a rim joist |
| Stain or sealer | 1 gallon per coat | Deck stain calculator: about 200 ft² per gallon. More for railings and steps |
Materials for other deck sizes
The first number is the length, the way the boards run. 5½ in boards, 1/8 in gaps, 16 in joist spacing, 10% waste:
| Deck size | Rows of boards | 12 ft boards | 16 ft boards | Joists | Screws |
|---|---|---|---|---|---|
| 8 × 10 ft | 22 | 17 | 13 | 7 | 308 |
| 10 × 10 ft | 22 | 21 | 16 | 9 | 396 |
| 12 × 12 ft | 26 | 29 | 22 | 10 | 520 |
| 12 × 16 ft | 35 | 39 | 29 | 10 | 700 |
| 16 × 20 ft | 43 | 64 | 48 | 13 | 1,118 |
What your plans must decide
These parts of a deck carry the load, so their size, number and spacing come from your plans, the building code and the soil, not from a calculator:
- Footings and posts. For example, if your plans call for six 12 in footings poured 3 ft deep, they take about 26 bags of 80 lb concrete (a sonotube calculator sizes any footing). Footings usually have to go below the frost line.
- Beams and the ledger board that carries the joists, and the flashing and fasteners that attach it to the house.
- Railings and stairs. Most codes require a guardrail on decks above about 30 inches, with rules for height and baluster spacing, and stairs have their own limits.
- A permit and inspection. Most decks need both, especially if attached to a house.
Choosing board length and layout
- Boards as long as the deck mean no butt joints, which are weak points and must land on a joist. A 16 ft deck suits 16 ft boards. The deck boards guide shows how to compare lengths to keep the cutoffs small.
- A diagonal layout or a picture-frame border adds cuts: allow 15% waste, and use joists at 12 inches.
- Pressure-treated boards shrink as they dry, so lay them close to flush. Composite and kiln-dried boards need the gap the maker specifies.
Estimates only. Decks are structures people stand on, often well above the ground: have the design checked by your building department.
Frequently asked questions
How many deck boards for a 12x16 deck?
29 boards of 16 ft, or 39 boards of 12 ft, using 5½ inch boards with 1/8 inch gaps and 10% waste. That is 26 rows across the 12 ft width.
How many joists for a 12x16 deck?
13 joists at 16 inches on center, each 12 ft long. At 12 inch spacing it is 17, and at 24 inches 9. Joist size and span must follow your local code.
How many screws do I need for a deck?
About 676 for a 12 × 16 deck: two for every board at every joist it crosses. Buy extra, since some strip or get dropped.
Does a deck need a building permit?
Usually yes, especially if the deck is attached to a house or stands more than a foot or two above the ground. The permit also brings an inspection of the footings and framing. Check with your building department before you order.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.