Free Deck Building Checklist: Permits Through Final Inspection (2026)

In most jurisdictions, yes. Any deck that is attached to the house or more than 30 inches above grade requires a building permit (IRC R105.2). Some areas also require permits for decks at ground level if they exceed a certain square footage. Freestanding decks under 200 sq ft and under 30 inches high are exempt in many locations, but check your local code. Building without a permit creates liability, hurts resale value, and can result in a forced teardown.

Deck footings must extend below the local frost line. Frost depth varies by region: 12 inches in the southern US, 24-36 inches in the mid-Atlantic and Pacific Northwest, and 42-48 inches in the upper Midwest and New England. Your local building department publishes the exact frost depth requirement. Footings above the frost line will heave during freeze-thaw cycles, cracking concrete and shifting the deck structure.

A pressure-treated wood deck costs $15 - $25 per square foot installed, including framing, decking, and basic railing. A composite deck runs $30 - $60 per square foot depending on the brand and features. A typical 300 sq ft deck costs $6,000 - $10,000 in pressure-treated wood or $12,000 - $20,000 in composite. Add $1,000 - $3,000 for stairs, built-in benches, or complex shapes. Use our Deck Cost Calculator for a detailed estimate.

Standard deck joist spacing is 16 inches on center for most decking materials. Composite decking and diagonal decking patterns often require 12 inches on center to prevent sagging between joists. Always check the decking manufacturer installation guide for their required joist spacing. Wider spacing saves on lumber but can lead to a bouncy feel underfoot and void the decking warranty.

Joist size depends on the span (distance between supports). 2x6 joists span up to 7-8 feet at 16" OC. 2x8 joists span up to 10-11 feet. 2x10 joists span up to 13-14 feet. 2x12 joists span up to 16-17 feet. These are approximate spans for #2 Southern Pine or Douglas Fir. Check IRC Table R507.5 for exact allowable spans based on species, grade, spacing, and live load. Use our Joist Span Calculator for quick planning numbers.

The ledger board must be lag-bolted or through-bolted to the house rim joist. Typical fastening: 1/2-inch lag screws at 16 inches on center, staggered in two rows. IRC Table R507.9.1.3 provides exact spacing based on joist span. Never use deck screws alone for ledger attachment. Ledger failure is the #1 cause of deck collapses in the US, causing injuries and deaths every year. Also install Z-flashing or self-adhering membrane behind the siding and over the top of the ledger to prevent water intrusion.

The maximum opening between balusters is 4 inches (IRC R312.1.3). A 4-inch sphere must not be able to pass through any opening in the railing system. This applies between balusters, between the bottom rail and the deck surface, and between the last baluster and the post. The minimum railing height is 36 inches for residential decks in most jurisdictions.

A typical 300 sq ft deck takes 3-5 days for a two-person crew, assuming footings are already cured. Add 1-2 days for footing excavation and concrete. Complex designs with multiple levels, stairs, built-in seating, or curved railings can take 7-10 days. The permitting and inspection process adds 1-3 weeks of calendar time depending on your jurisdiction. Weather delays are common for outdoor work, so build buffer into your schedule.