Piles sitting on the ground

Causes

Previous building work is inadequate or very old 

Listed under: concrete and cement, timber and wood-based, timber, Subfloor, bracing, framing, piles

Cause

Previous building work is inadequate or very old 

Repair

  • install new H5-treated timber piles or precast concrete piles. Follow NZS 3604:2011 Timber-framed buildings, Section 6

  • Getting the fixings right is important:

    • concrete piles are fixed to bearers with 4 mm wire threaded through a hole in the top of the pile and then stapled to the bearer with 4 staples at each end of the wire. The wire is hooked to form a U around the end staple to allow the wire to be pulled tight before the remaining staples are driven across both wires of the U

    • with 125 mm square H5‐treated timber piles, use 2/4.9 mm wire dogs plus 2/100 x 3.75 mm nails skew fixed into the top of the pile or 4/100 x 3.75 mm nails skew fixed into the top of the pile.  

    • fixings should be hot-dip galvanised, or stainless steel in exposure zone D, or in zones B and C where the top of the timber pile is less than 600 mm from the ground or the floor has more than 7000 mm2 of clear vent area per m2 of floor

    • where the tops of timber piles are within 300 mm of the ground (minimum height from ground to the top of a pile is 150 mm), a DPC is required between the pile and the bearer.

  • repiling falls into the category of ‘restricted building work’. When done by a contractor, it must be carried out or supervised by a licensed building practitioner with a Foundations licence

  • if only a few piles are sitting on the ground, replacing these in the same location will not require a building consent (but still needs to comply with the Building Act). Repiling all of a house or a substantial area will require building consent.

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