Gable Restraint System
Class 2a Buildings / houses of single occupancy five storeys or less England & Wales and four storeys or less Scotland
Timber Gable to Masonry fixing detail to cold roofs – continuous wallplate
Gable Panel
225mm maximum height between underside of wallplate and horizontal restraint strap
Insulation continued into gable panel
Breather membrane to face of gable panel
Roof insulation Longitudinal truss bracing
Continuous wallplate 38mm min-75mm maximum depth Cullen FT Timber frame wall ties
Level of truss wallplate
Solid blocking between truss and gable panel at horizontal restraint strap positions Gable Panel to wallplate fixing - Paslode 3.1mm dia x min 75mm long smooth shank nails at maximum 100mm centres Vertical holding down strap plugged and screwed to blockwork at maximum 1.8m centres, Cullen VRS-900-100
Mortar bed
Cullen RST-3 restraint straps at maximum 750mm centres fixed to longitudinal truss bracing / additional longitudinal bracing with 8 no. 4 x 25mm steel screws fixed to gable panel stud with 3 no. 3.4 x 35mm square twist nails
Cullen Gable Restraint Bracket (GRB) at maximum 750mm centres Cavity insulation shown for indicative purposes only - thermal bridging and SAP calculations to be plot specific
Cavity trays and firestops to be detailed by building designer
Gable Panel (without gable ladder)
Cullen PFS restraint straps fixed to solid timber noggins between trusses at maximum 1250mm centres with 3.4 x 35mm square twist nails, 8 no. to noggins and 4 no. to gable panel (2 no. top face & 2 no. cavity face) Cullen RST-3 restraint straps at maximum 800mm centres fixed to additional longitudinal bracing with 8 no. 4 x 25mm steel screws fixed to gable panel stud with 3 no. 3.4 x 35mm square twist nails
Truss profile
Gable Panel (with or without gable ladder)
Continuous wallplate 38mm min-75mm maximum depth Bottom rail of gable panel
800mm max 800mm max
800mm max
800mm max800mm max
Mortar bed
750mm max 750mm max 750mm max 750mm max
Cullen Gable Restraint Bracket (GRB) at maximum 750mm centres
Cullen VRS-900-100 fixed to top of bottom rail with 4 no. 3.4 x 35mm square twist nails
1800mm maximum
Vertical restraint strap plugged and screwed to blockwork at maximum 1.8m centres - Cullen VRS-900-100 installed to top of gable panel bottom rail
The latest version of the technical guide will always be the digital format on our website.
Technical support: 01592 771132 / technical@itwcp.com / https://www.itwcp-offsite.co.uk 10
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