Light steel framed walls and floors

6.10.10Construction of load-bearing walls and external infill walls

Construction of load-bearing walls and external infill walls shall ensure adequate stability. Issues to be taken into account include:

  1. preparation
  2. anchoring
  3. accommodation of deflection.


The following should be in accordance with the design:

  • the setting out of the structure onto which the light steel frame is to be erected.
  • the transfer of loads from the light steel frame.

The supporting structure may have local deviations in level along its length, and packing will be required to achieve the required tolerances and to provide for effective load transfer.

Concrete kickers should be carefully formed, ensuring that the concrete is adequately compacted and the top surface is suitably flat and level.

Table 5: Acceptable methods of packing under frames

Gap under base railAcceptable packing
Less than 10mm Provide shims under each stud position.
10-20mmProvide shims under each stud position, and grout under the whole length of the base rail with cement:sand mortar.
More than 20mm Obtain advice from the frame designer/manufacturer.
Remedial work to the substructure may be required before erection commences.

Shims should be of pre-galvanised steel or other suitable material, e.g. not timber.

Wall frames should be checked to ensure that they are dimensionally accurate before erection commences.

LSF should be correctly positioned, square and plumb, and within the following tolerances:

  • the vertical position of members should be within +/-5mm per storey relative to the base.
  • the horizontal position of base rails should not vary in alignment by more than 5mm in 10m.


The frame should be anchored to resist both lateral movement and uplift in accordance with the design, including bolt-down brackets where required.

Anchoring should ensure:

  • that appropriate edge details are provided and minimum edge distances specified by the fixing supplier are maintained, to avoid spalling of masonry or concrete
  • where fixings are into masonry, they are into solid concrete blocks with a minimum crushing strength of 7.3N/mm2 and positioned to receive fixings.

Where the design incorporates gas membranes (methane or radon), fixings should not puncture them, but where this is unavoidable, the penetration should be sealed.

Accommodation of deflection

Infill walls should accommodate anticipated deflection within the primary frame in accordance with the structural design.