Waterproof decks – impact or puncture damage

Causes

Careless walking on the roof or the membrane is not suitable for foot traffic 

There are sharp or hard objects on the roof

Nails in the substructure have popped, puncturing the membrane from underneath

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

Cause

Careless walking on the roof or the membrane is not suitable for foot traffic 

Repair

  • find out why people have been walking on the roof and determine how to avoid this situation recurring. For example, if people have been on the roof to carry out minor pruning on an overhanging tree, perhaps the branches need to be cut back further so that access from the roof is no longer necessary. Another option is to seek advice on whether the membrane can be covered with tiles or a floating deck suitable for foot traffic
  • if the damage is substantial, the membrane may need to be replaced
  • 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
  • application, repair or replacement of roofing membranes is restricted building work where a building consent is required. 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
  • carry out regular maintenance as recommended or required by the manufacturer/supplier

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Cause

There are sharp or hard objects on the roof

Repair

  • remove the hard or sharp objects and follow the guidance in the first repair above

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Cause

Nails in the substructure have popped, puncturing the membrane from underneath

Repair

  • since 2005, screws have been required to fix substrates under membrane roofs. If the substrate was constructed since then with nails, call back the company/tradesperson
  • follow the guidance in the first repair above. Where possible, determine why the nails have popped. If repairs are not possible and the membrane must be replaced, ensure the problems with the substrate are addressed before the new membrane is applied. The substrate should be fixed with screws and not nails

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