Pitched roofs


Battens and counter battens shall be adequately sized and spaced to support the roof covering.

Battens and counter battens should be:

  • in accordance with BS 5534, accompanied by a delivery note and marked with the supplier, origin, grade and size
  • preservative treated
  • where cut ends are in contact with mortar, treated with preservative
  • cut square, butt jointed over rafters and nailed to each rafter they span
  • fixed by skew driven nails on each side of the joint.

Counter battens should be fixed to the rafters and not only to sarking boards.

Battens should be:

  • a minimum of 1.2m long and span a minimum of three rafters
  • set out in straight lines parallel to the ridge and to the gauge required for the tile or slate (the lap should not be decreased as this would reduce weathertightness)
  • set out so that the tiles project a minimum of 50mm over the gutter
  • fixed through counter battens to rafters
  • where on rigid sarking boards, supported on counter battens
  • at verges, tile battens should finish 25mm-50mm from the face of the protecting undercloak
  • sized in accordance with the roof covering manufacturer’s recommendations, but not less than shown in Table 9.

Table 9: Suitable batten sizes

450mm span600mm span
Double lap slatesNatural: sized or random25mm x 50mm25mm x 50mm
Fibre cement or concrete25mm x 38mm25mm x 50mm
Clay/concrete tilesDouble lap25mm x 38mm25mm x 38mm
Single lap25mm x 38mm25mm x 50mm


1 Actual size should be within +/3mm of the nominal size.

Battens should be set out to avoid joints occurring over the same rafter. Where batten spacing is:

  • more than 200mm, no more than one batten in any group of four should be joined over any one truss or rafter
  • 200mm or less, no more than three joints should be made over any 12 consecutive battens.

Batten fixings should be:

  • cut or wire nails in accordance with BS 5534
  • a minimum of 3.35mm x 65mm long (10 gauge) and a minimum of 30mm longer than the batten thickness
  • ring shank nails where specified (where the maximum basic wind speed is over 26m/s (National Annex Figure NA.1 of BS EN 1991-1-4), galvanized smooth round nails are not acceptable and ring shank nails should be used)
  • hot dip galvanised steel or aluminium, when used in coastal areas
  • in accordance with manufacturer’s guidance where mechanical nail guns are used.