Texture-coated fibre-cement – vertical cracking at sheet joints

Some homes built with texture-coated fibre-cement claddings around the mid 1990s to the mid/late 2000s have had problems with leaks. This applies particularly to those with waterproof decks and parapets, no movement control joints, no eaves and complex designs. Engaging a registered building surveyor with experience in leaky homes is strongly recommended where a leak is suspected. DIY repairs and repairs by non-specialist builders often do not solve the problem and may result in further problems. See our Weathertight guide for more details.

Texture-coated fibre-cement claddings are typically proprietary systems. Where a problem such as cracking is found, contact the applicator/supplier for advice.

Causes

Flush-stopped joint not properly reinforced and stopped

Movement control joints not included 

Framing timber movement

Moisture entry into building structure

Building subjected to vibration movement such as earthquake, high wind

Common

Cause

Flush-stopped joint not properly reinforced and stopped

Repair

  • where there is no consequential damage identified by the building surveyor as a result of the cracking, the existing stopping can be scraped out and restopped using proprietary modified cement or acrylic stopping compound. A textured finish to match the existing external coating is then applied and repainted. A specialist/approved applicator may need to be engaged for this work

  • if evidence of leaking through the cladding cracks is found, engage a licensed builder who has experience in weathertight remediation work. A building consent will be required for repair work where the cladding has not met Building Code durability requirements

Cause

Movement control joints not included 

Repair

  • where there is no consequential damage identified by the building surveyor, movement joints can be installed at damaged joints by filling the joint with exterior grade sealant over bond breaker tape. Follow the manufacturer’s profile (shape factor for movement) requirements. (This is usually width that is double the depth, i.e. 2:1, and usually a minimum of 5 mm deep. If the factor is incorrect the sealant will not stretch and will break away from the sheet edge.) A finish to match the existing external coating is then applied. A specialist/approved applicator may need to be engaged for this work

  • if evidence of leaking through the cladding cracks is found, engage a licensed builder who has experience in weathertight remediation work. A building consent will be required for repair work where the cladding has not met Building Code durability requirements

Cause

Framing timber movement

Repair

  • where no consequential damage is identified by the building surveyor and the textured finish is relatively smooth, the joints can be covered with a painted 90 x 19 mm H3.2 treated batten. Each side of the batten should be bedded on a sealant bead

  • if evidence of leaking through the cladding cracks is found, engage a licensed builder who has experience in weathertight remediation work. A building consent will be required for repair work where the cladding has not met Building Code durability requirements

Cause

Moisture entry into building structure

Repair

  • engage a licensed builder who has experience in weathertight remediation work. A building consent will be required for repair work where the cladding has not met Building Code durability requirements

Cause

Building subjected to vibration movement such as earthquake, high wind

Repair

  • where there is no consequential damage identified by the building surveyor as a result of the cracking, the existing stopping can be scraped out and restopped using proprietary modified cement or acrylic stopping compound. A textured finish to match the existing external coating is then applied and repainted. A specialist/approved applicator may need to be engaged for this work

  • an alternative option where the textured finish is relatively smooth is to cover the joints with a painted 90 x 19 mm H3.2 treated batten. Each side of the batten should be bedded on a sealant bead

  • if evidence of leaking through the cladding cracks is found, engage a licensed builder who has experience in weathertight remediation work. A building consent will be required for repair work where the cladding has not met Building Code durability requirements