External timber framed walls

6.2.5Fixing the frame

The timber frame shall be suitably fixed to the substructure.


Where shotfiring:

  • into masonry, solid concrete blocks should be specified as BS EN 771 with a minimum crushing strength of 7.3N/mm2 and positioned to receive fixings
  • the blocks in beam and block floors should be grouted
  • care should be taken not to spall edges of masonry or slabs.


When anchoring the frame:

  • the sole plate should be adequately anchored to the substructure so that the frame can resist both lateral and vertical forces
  • care should be taken to avoid splitting timber plates or damaging the substructure.

Holding-down devices should be durable, as detailed in the design and manufactured from:

  • austenitic stainless steel to BS EN 10088-1, minimum grade 1.4301
  • galvanised mild steel with zinc coating to BS EN ISO 1461, minimum coating 940g/m2 on each side.

Sole plate anchors within the internal envelope should be galvanised mild steel, minimum coating Z275.