Ridge board
A ridge board is the horizontal timber at the apex of a pitched roof. AS 1684 sizes it by rafter span and wind class. Replaced by truss apex in trusses.
Ask Chalkline about this →A ridge board is the horizontal timber member at the apex (the ridge line) of a conventional pitched roof, against which the opposing rafters are fixed. It runs the full length of the ridge and ties the two rafter slopes together at the peak.
The ridge board is sized under AS 1684.2:2021 (non-cyclonic) or AS 1684.3:2021 (cyclonic), with span-table selection driven by rafter span, roof type (sheet or tile), and wind classification (N1 to N6, or C1 to C4 in cyclonic regions). The standard is the only authoritative size call for a specific span and load combination.
The ridge board sits against rafter end cuts on each face. Rafter fixings (nails or screws) drive through the rafter into the ridge board at angles set by the rafter pitch; AS 1684 specifies the fixing schedule for rafter-to-ridge connections.
A ridge board only exists in a conventional cut roof, where rafters are cut and fixed in-situ. In a trussed roof the ridge is formed by the apex connection of opposing top chords joined by the manufacturer’s metal nail plates; there is no separate ridge board. Truss apex layout is detailed by the truss manufacturer’s shop drawings, not AS 1684.
The chippy installs the ridge board and verifies the fixings at frame stage; the certifier confirms it at frame inspection.
Also known as: apex board.
Category: Roof framing / structural timber.
Related
- Roof framing (conventional cut roofs)
- Roof framing (trusses)
- Frame inspection checklist
- AS 1684 timber framing standard
See also
Last updated: 2026-05-14. Verified: 2026-05-14.