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Field guide / reviewed 2026-09-05

Read the assumptions before the span

A joist span is not a universal number. The published result changes with species, grade, size, spacing, load, deflection limit, service condition, treatment, use case, and code edition.

Start with the row, not the largest number

The reference table identifies a Southern Pine No.2 2 × 8 deck joist at 16 in OC, 40 psf live plus 10 psf dead load, L/360 deflection, wet service, incised pressure treatment, and DCA6 2015 as 11.1 ft.

Change the spacing to 24 in OC or change the species and the applicable row can change. That is why the joist lookup only returns a row when every displayed field matches a sourced entry.

Know what the lookup does not approve

The table is a planning lookup for the stated deck assumptions. It does not design beams, posts, connections, footings, lateral bracing, stairs, guards, snow loads, or unusual site conditions.

Use the local adopted code and a licensed professional for structural approval. Keep the species, grade stamp, treatment, and edition with the result when you discuss the member with a supplier or inspector.

Use the numbers

Published 2026-09-05. Updated 2026-09-05. Uzi Tools publishes planning estimates; local code, product instructions, and a licensed professional govern structural work.