Sheet membrane roofing – surface deterioration (cracking, crazing)

Causes

UV light degradation

Expansion/contraction of substrate resulting in over-stressing and failure of the membrane

Membrane (for example, a mineral chip surface on a polymer modified bitumen) is not suitable for foot traffic 

The material is at the end of its serviceable life

Listed under: membranes, sheet membranes, Roof, cladding, roof cladding, sheet membrane roofing

Cause

UV light degradation

Repair

  • membrane manufacturers/suppliers typically train and license applicators in the use of their membranes. Repairs or replacements should also be carried out by these trained/approved applicators. Work that is incompatible with the original membrane system may void the warranty and may make the problem worse

  • where the problem is severe and extends over a wide area of roofing, replacing the whole membrane may be a better long-term solution than just a repair

  • application or replacement of roofing membranes is restricted building work. Where done by a tradesperson, it must be carried out or supervised by a licensed building practitioner with the relevant licence class for that type of roofing

  • if the existing membrane must be replaced, and it has not met minimum Building Code durability provisions applicable (15 years), a building consent will be required

  • carry out regular maintenance as recommended or required by the manufacturer/supplier

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Cause

Expansion/contraction of substrate resulting in over-stressing and failure of the membrane

Repair

  • the substrate is likely to need repair/replacement. If the problem is the result of faulty substrate construction or membrane application, the repair or replacement should be made at the cost of whoever carried out that faulty work

  • follow the guidance in the first repair above

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Cause

Membrane (for example, a mineral chip surface on a polymer modified bitumen) is not suitable for foot traffic 

Repair

  • the membrane will most likely need replacing with one that is suitable. Follow the guidance in the first repair above. Check that any replacement membrane is appropriate for the circumstances, conditions and location

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Cause

The material is at the end of its serviceable life

Repair

  • the membrane will need replacing. Follow the guidance in the first repair above

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