Plywood flooring rotten

Cause

High subfloor moisture levels 

Repair

  • replace damaged flooring. If plywood is used in wet areas (for example, under waterproof membrane and tiles) it should be treated to H3.2 with CCA (not LOSP)

  • identify the cause of the subfloor moisture and address it. If it is caused by a leaking pipe, make a repair, or call a licensed or certifying plumber to repair it. Work on waste pipes and drains must by law be carried out by a licensed or certifying plumber

  • if surface water is flowing under the house, lower the ground levels around the building and slope the ground away from the house. Install channels or sub-surface drains and discharge into a stormwater drain or soak pit 

  • lay polythene sheeting at least 0.25 mm thick to cover the ground under the house. Ensure that the ground is shaped so no water accumulates on the polythene. Polythene sheets should be lapped a minimum of 150 mm, preferably taped, and butted up to foundation walls and piles. Weigh down the sheets with bricks or concrete to avoid them being displaced by air movement

  • improve subfloor ventilation

Cause

Cladding leak

Repair

  • address the cause of the leak and make repairs. Where the cause of the leak is difficult to identify or the leaks seem extensive, call an experienced building surveyor to investigate

  • replace damaged flooring. If plywood is used in wet areas (for example, under waterproof membrane and tiles) it should be treated to H3.2 with CCA (not LOSP)

Cause

Leakage or overflows occurring over a long period of time

Repair

  • identify the cause of leakage or overflows. Make a permanent repair where necessary, or call a licensed or certifying plumber to make repairs

  • where the cause of the leak is difficult to identify, call a plumber to investigate

  • replace damaged flooring. If plywood is used in wet areas (for example, under waterproof membrane and tiles) it should be treated to H3.2 with CCA (not LOSP)

Cause

Leaking from damaged or incorrectly installed shower tray or bath, or sealant failure around shower, bath, basin fittings

Repair

  • identify the cause of leakage. Make a permanent repair, or call a licensed or certifying plumber to make repairs

  • replace damaged flooring. If plywood is used in wet areas (for example, under waterproof membrane and tiles) it should be treated to H3.2 with CCA (not LOSP)

Cause

Impervious floor finish not installed or poorly installed in wet area spaces – kitchen, bathroom, laundry

Repair

  • replace damaged flooring. If plywood is used in wet areas (for example, under waterproof membrane and tiles) it should be treated to H3.2 with CCA (not LOSP)