A backyard deck is one of the highest-return outdoor projects you can tackle, adding usable living space and recovering 60% to 80% of the investment at resale. Deciding to build a deck yourself can save $5,000 to $15,000 in labor costs on a typical project, but it requires solid planning, the right materials, and a realistic assessment of your carpentry skills. This guide covers everything from permits to the final coat of stain.
Part of our Decks & Outdoor guide — explore the full guide →
Planning and Permits
Most municipalities require a building permit for any deck larger than 200 square feet or higher than 30 inches above grade. The permit application typically requires a site plan showing the deck’s location relative to property lines, a structural drawing with dimensions and footing details, and a materials list. Permit fees range from $75 to $500 depending on your area and the deck’s size.
Setback requirements vary but commonly mandate 5 to 10 feet from side property lines and 10 to 25 feet from rear lines. Zoning rules may also cap the total percentage of your lot that can be covered by structures. Skip the permit at your own risk; unpermitted decks can trigger fines, forced demolition, and complications when selling the home.
Choosing Decking Materials
Your choice of decking material affects cost, maintenance, appearance, and lifespan. Each option has clear trade-offs.
- Pressure-treated pine: $2 to $4 per linear foot. The most affordable option. Requires staining every 2 to 3 years and lasts 15 to 20 years. Splinters as it ages unless maintained.
- Cedar: $4 to $8 per linear foot. Naturally rot-resistant with a warm appearance. Lighter weight makes it easier to handle. Lasts 15 to 25 years with annual sealing.
- Composite (Trex, TimberTech): $6 to $12 per linear foot. Made from wood fibers and recycled plastic. Virtually maintenance-free, fade-resistant, and splinter-free. Lasts 25 to 50 years. Higher upfront cost but lower lifetime cost.
- PVC (AZEK, Fiberon): $8 to $15 per linear foot. Fully synthetic, 100% moisture-proof, and the lightest option. Best for waterfront properties and poolside decks. Lasts 30 to 50 years.
Regardless of the decking surface, the structural framing (posts, beams, and joists) should always be pressure-treated lumber rated for ground contact. Composite and PVC products are not designed for structural use.
Foundation and Footings
Proper footings are the foundation of a safe, long-lasting deck. Footings must extend below the frost line in your area, which ranges from 12 inches in the southern US to 48 inches or deeper in northern states. Undersized or shallow footings lead to frost heave, which can shift the entire deck structure over time.
Pour concrete footings using tube forms (Sonotube) set into holes dug with a power auger ($50 to $75 per day rental). Standard residential deck footings are 12 inches in diameter for single-story decks and 16 inches for elevated or multi-level structures. Set post bases or J-bolts into the wet concrete for anchoring the support posts. Allow 48 hours for concrete to cure before loading.
Framing the Deck
The ledger board attaches the deck to the house and must be properly flashed and lag-bolted to the rim joist, not nailed. Improper ledger attachment is the leading cause of deck collapses in the US. Use 1/2-inch lag bolts spaced 16 inches apart in a staggered pattern, and install self-adhering flashing tape behind and over the ledger to prevent water intrusion into the house framing.
Set beams on posts using approved post-to-beam connectors (Simpson Strong-Tie CB series). Hang joists from the beam and ledger using galvanized joist hangers spaced 16 inches on center for standard decking or 12 inches on center for diagonal decking patterns. Crown all joists upward so any natural bow works with gravity rather than against it.
Installing Decking Boards
Start the first board along the house edge, leaving a 1/4-inch gap between the board and siding for drainage and airflow. For face-screwed wood decking, use two stainless steel or coated deck screws per joist, pre-drilling near board ends to prevent splitting. Space boards 1/8 inch apart for drainage using a 16d nail as a spacer.
Composite decking typically uses hidden fastener systems that clip into grooves on the board edges, producing a screw-free surface. These systems cost $50 to $100 more per 100 square feet but create a cleaner look and eliminate mushrooming screw heads. Let composite boards acclimate on-site for 48 hours before installation to account for thermal expansion.
Railings and Stairs
Building code requires railings on any deck surface 30 inches or more above grade. Railing height must be at least 36 inches for residential decks (42 inches in some jurisdictions). Balusters must be spaced so that a 4-inch sphere cannot pass between them, preventing small children from getting through or stuck.
Stair construction follows specific code requirements: risers between 4 and 7-3/4 inches, treads at least 10 inches deep, and consistent dimensions throughout the entire run. A graspable handrail is required on at least one side. Pre-built stair stringer kits ($20 to $40 each) simplify the most complex part of deck stair building and ensure code-compliant geometry.
Finishing and Maintenance
If you build a deck with pressure-treated lumber, wait 2 to 4 weeks for the wood to dry before applying stain. A penetrating oil-based or water-based stain with UV protection ($30 to $60 per gallon) preserves the wood’s color and repels moisture. Apply with a pump sprayer and back-brush for even penetration. Plan to restain every 2 to 3 years for optimal protection.
Composite and PVC decking require almost no maintenance beyond periodic cleaning with a deck wash solution and soft brush. Remove leaves and debris regularly to prevent moisture trapping and mold growth between boards. Inspect all fasteners and structural connections annually, tightening any that have loosened from seasonal wood movement.
Total Cost to Build a Deck
A 300-square-foot pressure-treated pine deck costs $2,500 to $5,000 in materials for a DIY build. Professional installation doubles or triples that figure. The same footprint in composite decking runs $4,500 to $8,000 in materials, with professional installation adding $3,000 to $6,000 in labor. Factor in an additional $500 to $1,500 for railings, stairs, and permits. Despite the upfront investment, a well-built deck provides decades of outdoor living and measurably increases your home’s value.
How to Build a Deck Frame That Stays Square and Solid
When you build a deck frame, the order of work matters as much as the lumber. A frame laid out carefully goes together quickly, keeps the decking boards straight and resists the bounce and sway that make an older deck feel unsafe. Here are the layout and assembly steps that happen between setting footings and laying the first board.
Layout With String Lines and the 3 4 5 Check
Before any digging, set batter boards just beyond each outside corner and run tight string lines for the outer edges of the frame. Square the corner where the strings meet the house using the 3 4 5 method: measure 3 feet along one line and 4 feet along the other, and adjust until the diagonal between those marks is exactly 5 feet. Larger multiples such as 6, 8 and 10 give better accuracy. Then measure both full diagonals of the rectangle; when they match, the layout is square. Mark footing locations from the strings, and call 811 a few days ahead so buried utility lines are marked before you dig.
Assembly Order for the Frame
A typical sequence is ledger first, then posts, beams, rim joists and finally the inside joists. Cut posts long, then mark them to height with a level line from the ledger, allowing for the beam depth and a slight slope away from the house for drainage. Splice beam plies over a post rather than between posts, and fasten the plies together on a staggered pattern. Set the outer rim joists next so the frame becomes a box, check the diagonals again, and only then fill in the joists between them on the spacing your decking requires.
Blocking, Bracing and Protecting the Lumber
Solid blocking between joists at mid span stiffens the floor, keeps joists from twisting and reduces bounce. Taller decks need diagonal knee bracing between posts and beams to resist side to side movement, and many local codes now require lateral load connections that tie the deck frame to the house floor framing. Apply joist protection tape to the tops of joists and beams so water does not soak into fastener holes, and treat every cut end of pressure treated lumber with a matching end cut preservative. Use only connectors and fasteners rated for treated wood and outdoor exposure.
Permits and Structural Safety
A deck frame is a structural system that carries people, furniture, snow and wind loads, so it must follow the span tables, footing sizes and attachment rules your local building department enforces. Most areas require a permit and inspections for any deck attached to the house or raised above a modest height, and HOA rules may also apply. Ask the inspector to review the footings and framing before decking hides them. Leave a second story deck, a deck on a steep slope, or any ledger connection to an unusual wall to a licensed contractor or engineer. Framing lumber, hardware and connectors typically make up a large share of the total materials budget, so plan for them before choosing decking.
