Restraint Straps (Domestic Floors)
Lateral restraint of the walls can be provided by the floor, the restraint must be provided parallel and perpendicular to the floor joists.
ROOF
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.
3RD STOREY
2ND FLOOR
2ND STOREY
1ST FLOOR
1ST STOREY
GROUND FLOOR
3 STOREY HOUSE
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.
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.
Parallel Restraint
PSB strap with built in detail
— The strap should be nailed with a minimum of 8No 3.4x35mm Square Twist Nails into the joist bottom flange /chord
Floor Level
Detail
Region
Ground Floor
1st Floor
2nd Floor
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)
England & Wales
PSB straps re- quired at 2m max centres
Built in
Scotland
Please refer to page 5 for further information on PSB straps
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Technical support: 01592 771132 / technical@itwcp.com / https://www.itwcp-offsite.co.uk 8
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