Deck Calculator for a Ground-Level Deck
Estimate materials for a floating ground-level deck.
A ground-level (floating) deck sits on precast concrete deck blocks instead of buried footings — no permit needed in most jurisdictions if the deck is under 30 in high and not attached to the house. Use 2×6 joists on 16 in centers over blocks spaced 4–6 ft apart.
Deck boards
35
Joists
13
Screws
280
192 ft² deck
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How does the deck calculator work?
Board count = (deck length ÷ board length) × (deck width in inches ÷ board actual width). A "5/4×6" board is really 5.5 in wide. Joists at 16 in on-center: (length in inches ÷ 16) + 1.
Which guide explains this in more depth?
- Riser-and-tread math plus 2026 material prices for a full stair build. Read the stair calculator cost breakdown guide for the full worked example.
What else do people ask about this calculator?
Do I need a permit for a floating deck?
Usually no if it's under 30 in high, under 200 sq ft, and not attached to the house. Check your local building department to be sure.
How many deck blocks for a 10×12 floating deck?
9 blocks — three rows of three under the joists at ~4 ft spacing. Add 1 in of leveling gravel under each block.
How many deck boards for a 16×12 deck?
At 12 ft boards and 5.5 in actual width, about 27 boards plus 10% waste — order 30.
How far apart should deck joists be?
16 in on-center for standard decking; 12 in for composite or for spans over 12 ft.
Which related calculators should I use next?
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