Nailplate

A nailplate is a pressed steel plate with integral teeth punched into the timber to connect the joints of a prefabricated roof or floor truss. The plate’s position and embedment are part of the truss design, and side-loading can crack the teeth and void it.

Nailplates are how a truss holds together. At each joint where chords and webs meet, a plate is pressed into both faces of the timber so its teeth embed and transfer the load across the joint. The plates are sized and positioned by the truss designer’s software for the forces at each joint, so they are not interchangeable or relocatable on site, where the plate sits and how fully its teeth are embedded is structural.

A few things damage or invalidate a nailplate:

• Side-loading or impact during handling that bends the plate or partly lifts the teeth out.
• Partial embedment (a plate not fully pressed home, or pressed into split or wet timber).
• Corrosion in exposed or high-humidity locations where the plate galvanising is not rated for it.

For a builder the practical points are to handle trusses so the plates are not knocked or sprung (panel-point lifting, keep them in plane), never to remove, relocate, or “improve” a nailplate, and never to cut a member through or beside a plate. If a plate is lifted, cracked, corroded, or a joint has opened, it needs the truss supplier’s or an engineer’s repair detail, a screwed plywood gusset or a replacement plate to their specification, not a few extra nails. A sprung plate found at frame inspection is a hold-point, not a tidy-up.

Also known as: Nail plate, gang-nail plate, truss connector plate, punched metal plate.

Category: Roof framing / Trusses.

Related

• AS 4440 truss installation
• Bottom chord

See also

• Roof framing with trusses

References

• AS 4440 Installation of nailplated timber roof trusses, Standards Australia (verified 2026-06-01)

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Last updated: 2026-06-01. Verified: 2026-06-01. Quarterly review for currency.