Cracking/flaking of film on stained or clear-finished weatherboards

Causes

UV light deterioration

Moisture penetration and timber swelling

Mould growth

Loss of adhesion and flaking or peeling of finish

Listed under: Exterior, finishes, clear finishes, timber and wood-based, stain, timber, cladding, walls, moisture, mould, wall cladding, stained or clear-finished timber weatherboards

Cause

UV light deterioration

Repair

  • film-forming clear or lightly pigmented coatings are vulnerable to ageing of the underlying timber and loss of coating adhesion under UV light from the sun

  • some timber producers do not recommend clear finishes for timber elements fully exposed to sun and weather

  • recoating of clear or pigmented film-forming stains is likely to be required every 6 months–2 years

  • scrape or sand off the existing coating to give a clean, as-new timber surface. Recoating with the same type of product will restore appearance but frequent recoating will be required.

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Cause

Moisture penetration and timber swelling

Repair

  • prepare the weatherboards as above, but ensure that the timber is allowed to dry completely before recoating.

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Cause

Mould growth

Repair

  • prepare the weatherboards as above, but ensure that the timber is completely mould-free, clean and dry before recoating.

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Cause

Loss of adhesion and flaking or peeling of finish

Repair

  • prepare the weatherboards as above, ensuring that the timber is completely clean and dry before recoating.

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