Cullen Restraint Straps Technical Guide 2024

Restraint Straps (Domestic Floors)

PST strap with non–restraint hanger

— The strap should be nailed with a minimum of 8No 3.4x35mm Square Twist Nails into the joist top flange/chord

Lateral restraint of the walls can be provided by the floor, the restraint must be provided parallel and perpendicular to the floor joists.

Floor Level

Detail

Region

Ground Floor

1st Floor

2nd Floor

ROOF

Non–Restraint Hangers (JHI/JHIR/ RB–JHI/RB–JHIR)

England & Wales

PST or PSC required at 2m max centres

The type of restraint straps required and the centres at which they are placed depend on the joist end detail and region in which the house is built. Parallel restraint straps run along the same direction as the floor joists. Perpendicular restraint straps run across, or at a right angle to, the floor joists.

PST or PSC required at 2m max centres

PST or PSC required at 1.25m max centres

Scotland

Please refer to page 5 for further information on PST/PSC straps and table for the correct hanger / strap combination.

3RD STOREY

2ND FLOOR

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2ND STOREY

1ST FLOOR

PSB strap with restraint hanger

1ST STOREY

— The strap should be nailed with a minimum of 8No 3.4x35mm Square Twist Nails into the joist bottom flange/chord

GROUND FLOOR

Floor Level

Detail

Region

Ground Floor

1st Floor

2nd Floor

3 STOREY HOUSE

PSB required at 2m max centres PSB required at 1.25m max centres

Restraint Hang- ers (RA/HRAD/ RADS)

No additional restraint is required (additional PSB straps required each side of opening where openings exceed 600mm)

England & Wales

Scotland

The information we provide has been compiled using the minimum requirement from Building Regulations 2010 approved document A, Scottish Building regulation domestic, NHBC standards and British Standard BS 5628–1;2005 Annex D.

Please refer to page 5 for further information on PSB straps

These have been issued as guidance only, the overall responsibility lies with the Building Designer. For 3rd floor and above please refer to the building standards or building designer for guidance. All straps require a full storey of block work above to achieve the full 8kN declared load capacity.

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Parallel Restraint

PSB strap with built in detail

PSC strap with non–restraint hanger

— The strap should be nailed with a minimum of 8No 3.4x35mm Square Twist Nails into the joist top flange/chord

— The strap should be nailed with a minimum of 8No 3.4x35mm Square Twist Nails into the joist bottom flange /chord

Floor Level

Floor Level

Detail

Region

Detail

Region

Ground Floor

1st Floor

2nd Floor

Ground Floor

1st Floor

2nd Floor

Non–Restraint Hangers (JHI/JHIR/ RB–JHI/RB–JHIR)

England & Wales

PST or PSC required at 2m max centres

Where joists have a minimum bearing of 90mm no additional restraint is required (additional PSB straps required each side of opening where openings exceed 600mm)

PSB straps required at 2m max centres

England & Wales

Built in

PST or PSC required at 2m max centres

PST or PSC required at 1.25m max centres

Scotland

Scotland

Please refer to page 5 for further information on PST/PSC straps and table for the correct hanger / strap combination.

Please refer to page 5 for further information on PSB straps

Scan or click to view installation videos

Scan or click to view installation videos

The latest version of the technical guide will always be the digital format on our website.

The latest version of the technical guide will always be the digital format on our website.

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Technical support: 01592 771132 / technical@itwcp.com / https://www.itwcp-offsite.co.uk 9

Technical support: 01592 771132 / technical@itwcp.com / https://www.itwcp-offsite.co.uk

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