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How to Build a Deck: Complete Material Guide

From planning to finishing — calculate every material you need to build a deck, with cost estimates and pro tips at every step.

Building a deck is one of the highest-return DIY projects you can take on. A well-built deck adds outdoor living space, increases resale value, and can typically be completed by a determined homeowner over a few weekends. The hardest part isn't swinging the hammer — it's planning correctly so you buy the right amount of lumber, concrete, fasteners, and finish on the first trip to the lumberyard. This guide walks you through every step of building a standard residential deck, from setting footings to applying the final coat of stain. Along the way, we'll show you exactly which calculator to plug your measurements into so you can dial in your material list and budget before you spend a dollar.

Most ground-level decks under 200 square feet take a competent DIYer between 40 and 60 hours of labor, spread across two to four weekends. Larger or elevated decks can easily double that. Plan ahead, respect local codes, and use the calculators below to avoid the two most expensive mistakes in deck building: under-ordering boards (forcing extra trips and a mismatched second batch) or over-ordering by so much that hundreds of dollars of premium lumber sit warping in your driveway.

What You'll Need

Before you start, line up the tools and materials. Use the linked calculators to nail down quantities once you've finalized your deck dimensions.

Step 1: Plan Your Deck Size and Style

Start with a tape measure and a sketch. Walk the area where the deck will go and note where doors, windows, hose bibs, dryer vents, and electrical meters fall — these all dictate framing decisions. The most popular residential deck sizes are 10x12, 12x16, and 16x20. A good rule of thumb is to size your deck for the furniture and traffic you actually want: a six-person dining table needs at least 10x10 of clear space, and a grill station wants at least 4 feet of side clearance from any railing or wall.

Attached vs. Freestanding

An attached deck bolts to your house through a ledger board, which saves on posts and footings but introduces flashing, fastener, and waterproofing requirements that have caused many of the catastrophic deck collapses you read about. A freestanding deck uses its own beam and posts along the house side, eliminating the ledger entirely. Freestanding decks are often the simpler choice for first-time builders.

Permits and Codes

Most U.S. jurisdictions require a permit for any deck attached to a structure or any deck more than 30 inches above grade. Permit fees range from $50 to $500. Pulling a permit forces your design through an inspector's eye — a great safety net. Look up your local code's required footing depth (frost line), joist spacing (typically 16 inches on center for wood, 12 inches for composite), and railing height (36 or 42 inches depending on deck height) before you finalize your plan.

Step 2: Calculate Concrete Footings

Footings are the foundation of your deck — get them wrong and the entire structure suffers. Most residential decks use either poured concrete piers in tube forms (Sonotubes) or pre-cast concrete deck blocks for ground-level builds. For anything above 30 inches or attached to a house, code almost always requires poured concrete dug below the local frost line, which can be anywhere from 12 inches in the Deep South to 48+ inches in the Upper Midwest.

A typical 10x12 deck needs 6 footings; a 16x20 deck typically needs 9 to 12. Each 12-inch diameter footing dug 4 feet deep takes about 0.10 cubic yards of concrete. Plug your tube diameter and depth into our concrete calculator to get an exact bag count for 60-lb or 80-lb pre-mix bags. For pricing, see our concrete cost guide, which breaks down ready-mix delivery vs. mixing by hand.

Setting Footings the Right Way

Dig holes with a post-hole digger or rented two-person auger. Drop in cardboard tube forms, level the tops, and pour concrete to within an inch of the rim. Set galvanized post bases into the wet concrete rather than burying wood posts directly — direct burial cuts post lifespan in half. Let footings cure at least 24 hours before loading them, ideally 72 hours.

Step 3: Estimate Decking Boards and Joists

The framing skeleton — beams, joists, ledger, and rim — accounts for roughly 40% of your lumber budget. The decking on top accounts for the other 60%. Standard joist spacing is 16 inches on center for diagonal decking patterns, 16 inches for parallel patterns with most wood, and 12 inches on center for composite decking running perpendicular (or even tighter for diagonal composite).

Use our decking calculator to plug in your deck length, width, board width (typical 5.5 inches actual for 6-inch nominal), and joist spacing. The tool returns the linear feet of decking, total board count, and a recommended waste factor (typically 10% for straight runs, 15% for diagonal patterns).

Choosing Wood vs. Composite

Pressure-treated pine is the cheapest option at $2 to $4 per linear foot for decking, but requires staining every 2 to 3 years. Cedar runs $3 to $7 per foot and offers natural rot resistance with a beautiful color that ages to silver-gray. Composite decking like Trex or TimberTech runs $4 to $12 per linear foot, requires almost no maintenance, and typically lasts 25+ years. Our composite vs. wood decking comparison walks through the lifetime cost math, which often favors composite once you factor in 20 years of staining.

Fasteners

For wood decking, plan on two screws per joist intersection, which works out to about 350 screws per 100 sq ft. For composite, hidden fasteners or color-matched screws are standard. Always use stainless or coated decking screws — drywall screws and basic deck screws will rust through and stain your boards within a year.

Step 4: Build the Deck Stairs

Stairs are the most code-sensitive part of any deck. Inspectors look hardest here because uneven rises and shallow treads cause the majority of deck-related injuries. The standard U.S. residential rules: rise no greater than 7.75 inches, tread no less than 10 inches, and variation between any two steps under 3/8 inch.

Our deck stair calculator handles the math: enter total rise (deck-top-to-ground), and it returns the number of steps, exact rise per step, run, and recommended stringer length. From there you can either cut your own 2x12 stringers or buy pre-cut ones from a big box store. Most decks need a minimum 36-inch wide stairway; 42 to 48 inches feels noticeably more comfortable.

Stair Hardware

Attach stringers to your rim joist with stair-stringer hangers — never just toenail them. The bottom of each stringer should rest on a small concrete pad rather than bare dirt, which will heave with frost and warp the entire stair over a few seasons.

Step 5: Apply Stain or Sealer

Wait at least 30 days after building before staining pressure-treated lumber so it can dry out — staining wet lumber traps moisture and causes peeling. Cedar and other naturally rot-resistant woods can be stained right away if they're dry. Composite decking should never be stained; just rinse it.

Use our stain calculator to figure out exactly how much you'll need. A 10x12 deck needs roughly 1 to 1.5 gallons for one coat at 200 sq ft per gallon coverage, plus extra for railings and stairs (figure 25% more). Use a semi-transparent or solid stain depending on whether you want grain visible. Apply with a pump sprayer for speed and back-roll with a pad applicator to drive stain into the grain.

Maintenance Cadence

Pressure-treated and cedar decks should be cleaned and re-stained every 2 to 3 years depending on sun exposure. Annual maintenance is just a soft-wash with deck cleaner each spring.

Step 6: Total Project Cost

Total cost depends heavily on size, decking material, and how much labor you do yourself. Here are typical all-in DIY costs for common deck sizes (materials only — labor adds 50% to 100%):

Deck Size Pressure-Treated Cedar Composite
10x12 (120 sq ft) $1,400 – $2,200 $2,200 – $3,300 $3,500 – $5,500
12x16 (192 sq ft) $2,200 – $3,500 $3,400 – $5,300 $5,400 – $8,500
16x20 (320 sq ft) $3,500 – $5,800 $5,500 – $8,800 $8,800 – $14,000

For a complete breakdown of national averages, hidden costs (permits, dumpster rental, delivery), and contractor pricing, see our full deck cost guide.

Pro Tips for Building a Deck

Common Mistakes to Avoid

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