Surface of liquid applied-roofing membrane buckling or cracking

Causes

Poor initial installation 

Insufficient number of movement control joints resulting in buckling or cracking of the membrane

UV degradation

Lack of maintenance – liquid-applied membranes must be re-applied every 7–10 years

Membrane is at the end of its serviceable life

Movement in the plywood substrate

Listed under: membranes, Roof, cladding, moisture, roof cladding, leaks, weathertightness

Cause

Poor initial installation 

Repair

  • if the membrane roofing was applied by a tradesperson relatively recently – within the last few years – call them back. If the problem is the result of faulty application of the membrane (in other words, the membrane manufacturer is not at fault), the repair or replacement should be made at the cost of whoever carried out that work

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

  • 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 a repair

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

  • if the problems mean 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

Insufficient number of movement control joints resulting in buckling or cracking of the membrane

Repair

  • as above. It is likely that work will be required on the substrate as well as replacing the membrane

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Cause

UV degradation

Repair

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

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Cause

Lack of maintenance – liquid-applied membranes must be re-applied every 7–10 years

Repair

  • the membrane will most likely need replacing. Follow the guidance in the first repair above. Carry out regular maintenance as recommended or required by the manufacturer/supplier

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Cause

Membrane 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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Cause

Movement in the plywood substrate

Repair

  • as the first repair above. It is likely that work will be required on the substrate as well as replacing the membrane

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