- Cladding may be fixed to an existing property in one of three ways :
1.1 Fixed to cladding battens that are fastened directly to the outer wall through the vapour barrier and non compressable insulation using special fixings or, more preferably:
1.2 Fixed to cladding battens and counter battens (if used) over secondary battens/studding attached separately to the wall (as in the drawing) or
1.3 Where there is concern about additional loads being attached or the wall is uneven/out of true, the cladding may be fixed to battens attached to a self supporting treated timber frame.
- Waterproof membrane: Solid walls shall be protected from water penetration by either a water repellent coating or breather membrane. Fitting a breather membrane between cladding battens attached to a cavity wall structure is not essential.
Insulation: If adequate insulation already exists within the walls of the building, the batten supports can be fitted directly to the external wall.
- Batten size: Battens should be at least 2.0 times the thickness of the board profile. Battens at 400mm centres should be used for diagonal cladding or where boards with high moisture content are to be used e.g. green oak.
- Where horizontal boards abut one another additional support shall be provided by a second batten that extends at least the width of one board either side of the abutting boards.
- A cavity of at least 21mm shall be incorporated into the design to permit air circulation and unrestricted drainage of rainwater that penetrates the cladding. The more open the cladding joints then the width of the cavity shall be increased. All openings into the cavity should be fitted with insect mesh.
- Treatment: Softwood battens/studding/support frame shall be pre-treated by an industrial process in accordance with BS8417 for a BSEN335:1 Use Class 3 application - Wood Protection Association Commodity Specification Code: C6. This code is also referred to in NBS as Z12/120).