Cladding may be fixed to an existing property in one of three ways:
Fixed to cladding battens that are fastened directly to the outer wall through the vapour barrier and non-compressible insulation using special fixings or, more preferably:
Fixed to cladding battens and counter battens over secondary battens/studding attached separately to the wall (as in the drawing) or;
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.
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 where water repellent insulation is used.
Batten size: Battens should be at least 2.0 times the thickness of the board profile.
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)
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.