Cracked or damaged subfloor sheet cladding

Cause

Building movement

Repair

  • check that damage is limited to the subfloor sheet cladding and has not affected the piles or subfloor framing or bracing. (If you think damage may affect piles, subfloor framing or wall framing above, consult a chartered professional engineer)

  • remove all cracked and damaged subfloor sheet cladding and replace with new. Ensure the base of the sheets is clear of the ground or paving

  • use galvanised steel fixings, or stainless steel fixings in coastal areas where there may be salt spray

  • install vents in the sheeting (with proprietary grille covers) to ensure subfloor ventilation is maintained:

    • ensure there is not less than 3500 mm² of clear open subfloor venting for every 1 m² of building floor area

    • make ventilation openings high in the subfloor space, near to the underside of bearers

    • spread vents evenly around the building perimeter to allow cross-ventilation

  • when properly fixed to piles, subfloor framing or jack studs (see drawing), sheet cladding acts as bracing, strengthening a building against potential earthquake damage.

  • two BRANZ bulletins can give further guidance: BU536 Upgrading piled foundations to resist earthquakes and BU674 Seismic retrofitting houses with piled foundations on sloping sites

Cause

Earthquake

Repair

  • as for repair above. If earthquake damage is extensive, consult a chartered professional engineer
  • if you have a home insurance policy that includes fire insurance (most of them do), you have cover under Toka Tū Ake EQC (the Earthquake Commission). You can find more details here

Cause

Impact damage 

Repair

  • as for the first repair above.

Cause

Sheets have become brittle with age

Repair

  • as for the first repair above.