Waterproof decks – deterioration under cantilevered balcony

Cause

Inadequate drainage from the balcony 

Repair

  • if the waterproof deck was built within the last 10 years, call back the original builder/installer so the repair can be made by the contractor who carried out the original work. If the problem is the result of faulty building work, the repair should be made at the cost of whoever carried out that work
  • the extent of deterioration under the balcony must be fully understood and repaired before any other work is done. Consulting an experienced building surveyor is a good option
  • a fully enclosed deck should have at least two drainage outlets with independent overflows – a single drainage outlet is not good design
  • if repairs require removal of the original membrane, then a new membrane should be installed only after repairs are complete, the framing and substrate is sound and appropriate drainage has been selected
  • membrane manufacturers/suppliers typically train and license applicators in the use of their membranes. Installation of membranes is not something suitable for DIYers

Cause

Damage or penetrations through the decking membrane

Repair

  • the general points in the first repair above apply here too. Before repairing or replacing the membrane it is crucial to check whether or not there is any damage in the substrate or framing below it. An experienced building surveyor can help with this

Cause

Water entry into the balcony floor and/or wall framing

Repair

  • as for the first repair above