16x20 deck materials list and cost estimate
A 16 × 20 ft deck — 20 ft along the house and 16 ft out — comes to $5,240 in materials with Trex Transcend decking at US-average home-center prices (±15%, updated Aug 2026). The numbers below come from the free designer; the $19 unlock adds the itemized list and the build guide for your exact design.
Sized from span tables for pressure-treated 2x8 joists at 16" on center, ledger-attached to the house, with a (2) 2x12 built-up beam on 6x6 posts. At 16 ft out, the joists need 1 intermediate beam line to keep the span in table range.
Every one of these is adjustable in the designer — joist size and spacing, species, post size, footing type, soil bearing, cantilever, height, stairs, and railings — and the framing re-checks itself as you edit.
- · Deck surface is over 30" above grade — a guardrail is code-required. Enable railings.
- · 2x8 @ 16" OC can't span the full 16 ft, so 1 intermediate beam was added (clear span now 7.5 ft). A 2x12 joist would span it with no extra beam.
Base deck only: decking, framing lumber, footings, connectors and fasteners, with waste allowances. Stairs and a guardrail (required above 30") add to this — switch them on in the designer and the estimate updates. Enter your ZIP for regional pricing.
All 13 line items across 4 categories — decking, framing lumber, footings, connectors & fasteners — each with quantity, stock length, unit and total cost. Check items off as you buy, export to CSV, or print.
Enter your ZIP and every price is scaled by a regional materials cost index, with the local frost depth driving footing depth and concrete.
From layout and footings through ledger, beams, joists, decking, stairs and railings — every number pulled from your design, with dimensioned detail drawings at each step.
Change the design after buying and the list and guide follow it — one unlock covers the design and its revisions.