Waterproof decks – membrane turn-ups improperly installed

Causes

Poor detailing and/or installation to membrane turn-ups at walls and doors (potentially allowing water entry)

The waterproofing membrane was applied/laid after the cladding was installed

Listed under: Exterior, membranes, balconies, cladding, decks, moisture, leaks, weathertightness

Cause

Poor detailing and/or installation to membrane turn-ups at walls and doors (potentially allowing water entry)

Repair

  • if the membrane was installed in recent years, call the installer back. Membranes still under warranty should be repaired by the contractor who carried out the original application or by another applicator approved by the membrane supplier

  • installation and/or repair of membranes is not a DIY job. Membrane manufacturers and suppliers typically train and license applicators in the use of their products. A warranty may only apply where application or repair is carried out by someone licensed by the supplier

  • the Building Code Acceptable Solution E2/AS1 requires the membrane to be turned up 150 mm under cladding and also has specific requirements around doors (Figure 62 in E2/AS1, which can be accessed from here. 

  • where there is a habitable space beneath the waterproof deck, work on the membrane is restricted building work under the Building Act and anyone engaged to carry out this work must be a licensed building practitioner or supervised by an LBP

  • if you suspect that water has got into the building (inside the walls, for example) engage a building surveyor to look at this and advise on options

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Cause

The waterproofing membrane was applied/laid after the cladding was installed

Repair

  • as for the first repair

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