Paint failure – textured coatings

With flush-finished, texture-coated fibre-cement claddings, the paint coating creates a weatherskin. Maintaining this is crucial to the long-term weathertightness and durability of the cladding. Any faults in the cladding or paint coating should be repaired immediately. Houses with this type of cladding built around the mid-1990s to the mid-2000s have figured in leaky building statistics. If you think there is a risk that moisture has got into the cladding or framing, consult an experienced building surveyor from the New Zealand Institute of Building Surveyors.

Causes

Weathering, UV light exposure

Poor initial substrate preparation

Loss of adhesion due to excess moisture in substrate

Coating applied over a damp or dirty surface

Coating at end of its serviceable life

Pinhole defects in original coating

Listed under: Exterior, concrete and cement, fibre-cement, cladding, walls, moisture, wall cladding, fibre-cement cladding

Cause

Weathering, UV light exposure

Repair

  • many texture-coated fibre-cement claddings are proprietary systems that are installed by trained and approved applicators. Contact an applicator or supplier for recommendations as to what action to take and/or what materials to use

  • if the coating remains intact but has just faded or chalked, recoating with the recommended product may be possible. Clean thoroughly to remove dust and dirt using water and a brush (do not waterblast). If moss or mould is present, treat surface with fungicide and rinse well. Paint with a minimum two coats of approved acrylic coating in accordance with the manufacturer or supplier’s instructions

  • once the repair has been completed, carry out regular maintenance as recommended or required by the manufacturer/supplier

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Cause

Poor initial substrate preparation

Repair

  • as in the repair above but note that, if the textured coating is in poor condition, full removal may be necessary to allow proper preparation of the substrate for new coating to be applied. Applying new texture coating should be carried out by a trained operator

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Cause

Loss of adhesion due to excess moisture in substrate

Repair

  • as in the first repair above but note that, depending on the condition of the texture coating, full removal may be necessary to allow proper preparation of the substrate for new coating to be applied. Applying new texture coating should be carried out by a trained operator

  • moisture in the substrate must be fully addressed before the cladding can be recoated. The moisture may be an indication of leaks – consult an experienced building surveyor from the New Zealand Institute of Building Surveyors

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Cause

Coating applied over a damp or dirty surface

Repair

  • as in the first repair above but note that, depending on the condition of the texture coating, full removal may be necessary to allow proper preparation of the substrate for new coating to be applied. Applying new texture coating should be carried out by a trained operator

  • if there is moisture in the substrate, this must be fully addressed before the cladding can be recoated. The moisture may be an indication of leaks – consult an experienced building surveyor from the New Zealand Institute of Building Surveyors.

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Cause

Coating at end of its serviceable life

Repair

  • the coating will need to be replaced, as outlined above

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Cause

Pinhole defects in original coating

Repair

  • as in the first repair above

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