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UK Timber Connectors & Straps Guide
Framing anchors, truss clips, joist straps and restraint straps with sizes, fixing requirements and BS EN 14545 references.
Framing Anchors
L-shaped connectors for joining joists, rafters and studs to plates and beams. Comply with BS EN 14545.
| Type | Dimensions (mm) | Fixing | Typical Use |
|---|---|---|---|
| Standard framing anchor | 38 x 100 x 59 | 4 x 30 mm nails per leg | Joist to wall plate, rafter to plate |
| Heavy-duty framing anchor | 47 x 133 x 75 | 6 x 30 mm nails per leg | Heavy rafters, trimmer connections |
| Skewable framing anchor | 38 x 128 x 63 | 5 x 30 mm nails per leg | Angled connections, hip rafters |
Truss Clips
Secure roof trusses to the wall plate, resisting uplift forces.
| Type | For Truss Width (mm) | Fixing | Uplift Resistance (kN) |
|---|---|---|---|
| Standard truss clip | 35–47 | 3 x 30 mm nails each side | ~2.0 |
| Heavy-duty truss clip | 35–75 | 4 x 30 mm nails each side | ~3.5 |
Restraint Straps
Required by Approved Document A to tie walls, floors and roofs together. Minimum specification: 30 x 5 mm galvanised mild steel.
| Strap Type | Length (mm) | Section (mm) | Application |
|---|---|---|---|
| Lateral restraint (straight) | 1000 | 30 x 5 | Joists parallel to wall, across 3 joists |
| Lateral restraint (bent) | 1100 | 30 x 5 | Joists perpendicular, turned down wall |
| Heavy-duty restraint | 1200–1500 | 30 x 5 | Gable walls, high-exposure sites |
Joist Straps & Noggin Straps
| Type | Typical Size | Use |
|---|---|---|
| Herringbone strutting | 38 x 38 mm timber or metal | Between joists to prevent twisting (spans over 2.5 m) |
| Solid blocking | Same depth as joist | Between joists at supports and mid-span |
| Metal herringbone strut | Adjustable 150–250 mm depth | Quick-fit alternative to timber strutting |
Related Calculators
See the Joist Hanger Sizes guide for hanger specifications, or the Timber Span Calculator for sizing joists. See also the Timber Connector Calculator.
Next up: related pages
Frequently Asked Questions
Restraint straps tie the roof and floor structure to the walls to resist lateral forces (wind uplift and racking). Under Approved Document A, 30 x 5 mm galvanised mild steel straps (minimum 1000 mm long) must be fitted at maximum 2 m centres at roof level and at floor levels where walls exceed 3 m height. Straps must be fixed to at least three joists or rafters with the specified number of fixings.
Most timber connectors require 3.75 x 30 mm or 4.0 x 30 mm connector nails (not standard wire nails). These short, thick nails are designed to maximise shear strength in the thin metal. Every pre-punched nail hole must be filled for the connector to achieve its rated load. Some heavy-duty connectors also require coach screws or bolts — always check manufacturer data.
All timber connectors used externally or in contact with treated timber must be galvanised (minimum Z275 coating) or stainless steel. Interior connectors in dry conditions can be plain steel, but galvanised is standard practice for all structural applications. Stainless steel (A2 or A4) is required in marine or highly corrosive environments.
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Last updated: April 2026
Verified against UK standards · estimates only, confirm with your supplier.