Piled foundations – loose bolt fixings


Timber shrinkage has occurred since the bolts were installed or the bolts were not tightened originally


  • tighten bolts as necessary. In NZS 3604:2011 Timber-framed buildings, open subfloors are regarded as ‘sheltered’ environments. Bolts should at the least be hot-dip galvanised. All connections to treated timber piles within 600 mm of the ground, and/or in coastal areas, must be 304 stainless steel.

  • 50 x 50 x 3 mm washers must be used with the bolts.