Texture-coated fibre-cement cladding – paint failure at base of walls

Cause

Cladding covered by soil/foliage

Repair

  • lower the soil level to leave a minimum 30–50 mm gap between the base of the cladding and the ground. This is less than the gap required in new construction (which for this cladding is 100 mm above a paved surface or 175 mm above a finished unpaved surface) but could reduce the risk of moisture uptake and allow the cladding to dry. The new construction requirements should be used if possible

  • with suspended floors, ensure that lowering the garden level does not lead to rainwater flowing under the house

  • replace larger plants that are covering or damaging the cladding with smaller plants

  • when repainting, follow the instructions of the cladding/paint manufacturers. Ensure that the bottom edge of the cladding is painted to provide a seal

  • if damage behind the cladding is suspected – rot in framing timbers, for example – consult a registered building surveyor for advice

Cause

The cladding is too close to the ground, not sealed and absorbing moisture

Repair

  • the cladding must be well clear of the ground – aim for at least a 30–50 mm gap. This is less than the gap required in new construction (which for this cladding is 100 mm above a paved surface or 175 mm above a finished unpaved surface) but could reduce the risk of moisture uptake and allow the cladding to dry. The new construction requirements should be used if possible

  • with suspended floors, ensure that lowering the garden level does not lead to rainwater flowing under the house

  • when repainting, follow the instructions of the cladding/paint manufacturers. Ensure that the bottom edge of the cladding is painted to provide a seal

  • if damage behind the cladding is suspected – rot in framing timbers, for example – consult a registered building surveyor for advice

Cause

Concrete has been placed up to and against cladding

Repair

  • break up and remove the concrete against the cladding to leave a minimum 30–50 mm gap between the base of the cladding and the ground. This is less than the gap required in new construction (which for this cladding is 100 mm above a paved surface or 175 mm above a finished unpaved surface) but could reduce the risk of moisture uptake and allow the cladding to dry. The new construction requirements should be used if possible. Ensure that rainwater flows away from the house

  • when repainting, follow the instructions of the cladding/paint manufacturers. Ensure that the bottom edge of the cladding is painted to provide a seal

  • if damage behind the cladding is suspected – rot in framing timbers, for example – consult a registered building surveyor for advice

Cause

There are high subfloor moisture levels behind the cladding

Repair

  • first, deal with the problem of the subfloor moisture behind the cladding:

    • ensure good subfloor ventilation of not less than 3500 mm² of clear open subfloor venting for every 1 m² of floor area. Vents should be spread evenly around the building perimeter to allow cross-ventilation. No part of the subfloor should be more than 7.5 m from a ventilation opening

  • if the soil under the house is wet, see the repairs for Subfloor – damp soil

  • lay polythene sheeting at least 0.25 mm thick to completely cover the ground under the house. Ensure that the ground is shaped so no water accumulates on top of 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

  • inspect the condition of the cladding. Where damage is limited to the coating and the cladding itself is sound, allow it to dry out completely. Scrape off loose coating and sand lightly until the surface is sound. When the surface is dry and clean, recoat with at least 2 coats of acrylic paint. Ensure that the bottom edge of the cladding is painted to provide a seal

Cause

The bottom of the cladding is too close to the waterproof deck surface, apron flashing and absorbing moisture  

Repair

  • if even part of the cladding is in contact with the deck surface, water may wick up through the cladding into the framing behind and any water behind the cladding will be prevented from draining out. The long-term results can be damage to the paint finish, cladding and potentially rot in the framing

  • engage a registered building surveyor to report on the building condition and repair options (which are likely to be limited)

  • once a repair has been made and repainting is underway, ensure that the cut edge of the fibre-cement is allowed to dry and is then painted to provide a seal