6.3 Internal walls

Also see:

Structural design of load-bearing timber walls should be in accordance with BS EN 1995-1-1.

the underside of the lowest sole plate should be positioned at or above internal finished floor level, see Figure 8
individual studs, rails and head binders should be 38mm x 75mm minimum, although larger sizes may be required to achieve an adequate level of fire resistance
studs should be spaced at a maximum of 600mm centres
mid height noggings should be installed when required for additional stiffness
lintels and cripple studs should be provided to each opening, except when the stud spacing is unaffected
multiple studs should be included to support multiple joists, beams, girder trusses and other point loads, unless otherwise specified by the designer
where a head binder is not provided, joists, roof trusses and other similar loads should bear directly over studs
framing joints should be secured with a minimum of two nails per joint
where internal walls are made up from panels, structural continuity should be maintained, eg by the use of a continuous head binder.

The type and spacing of wall straps should limit sound transmission across the cavity in accordance with Building Regulations.

Timber should be of the appropriate grade, moisture content and size to support the imposed loads.

machine graded to BS EN 14081, or visually graded to BS 4978 for softwoods or BS 5756 for hardwoods
assigned a strength class based on BS EN 1912 when visually graded
dry graded
marked in accordance with BS EN 14081.

Further guidance on strength classes for certain timber species can be found in PD 6693.

Engineered wood products such as I-section or metal-web studs should be assessed in accordance with Technical Requirement R3.

Timber should have a maximum moisture content of 20% at the time of dry lining to minimise shrinkage.

Last updated: 2nd January 2024