Timber trims – splitting or cupping

Cause

Thermal expansion and contraction of timber

Repair

  • replace damaged boards. If replacement timber is radiata pine, it must be treated to H3.1 and be fully primed before installation (including the back), then given two topcoats of paint. Alternatively, use H3.2 if installed unpainted or stained
  • nail with single fixing in the centre of the batten

Cause

Swelling/shrinkage due to moisture absorption 

Repair

  • replace damaged boards. If replacement timber is radiata pine, it must be treated to H3.1 and be fully primed before installation (including the back), then given two topcoats of paint. Alternatively, use H3.2 if installed unpainted or stained
  • nail with single fixing in the centre of the batten

Cause

Back of painted boards not primed

Repair

  • replace damaged boards. If replacement timber is radiata pine, it must be treated to H3.1 and be fully primed before installation (including the back), then given two topcoats of paint. Alternatively, use H3.2 if installed unpainted or stained
  • nail with single fixing in the centre of the batten