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Appraisal number: 474 (2019)

Date issued: 13 Sep 2019

Flexi-Seal® Interior Waterproofing Systems


Flexi-Seal® Interior Waterproofing Systems are liquid-applied waterproofing membrane systems for use under ceramic and stone tiles in internal wet areas.


Flexi-Seal® Interior Waterproofing Membranes have been appraised for use as waterproofing membrane for internal wet areas of buildings, within the following scope:

  • On floor substrates of concrete, flooring grade particleboard, plywood, fibre-cement compressed sheet and fibre-cement sheet tile underlay and on wall substrates of wet area fibre-cement sheet lining systems and wet area plasterboard lining systems.
  • When protected from physical damage by ceramic tiles or stone finishes.
  • Where floors are designed and constructed such that deflections do not exceed 1/360th of the span.

The use of Flexi-Seal® Interior Waterproofing Systems on concrete slabs where hydrostatic or vapour pressure is present  from below is outside the scope of this Appraisal.

Movement and control joints in the substrate must be carried through the membrane and the tile finish. The design and construction of the substrate and movement and control joints is specific to each building and therefore the responsibility of the building designer and building contractor and is outside the scope of this Appraisal.

The ceramic or stone tile finishes are outside the scope of this Appraisal.

The membranes must be installed by trained installers, approved by RLA Polymers (NZ) Ltd.

Technical literature

  • Flexi-Seal Licensed Waterproofing System, 08/05/2018
  • Flexi-SEAL PUD 

Consenting instructions

Always refer to the Appraisal in full and the technical literature.

Appraisal holder

RLA Polymers (NZ) Ltd
Phone: 09 267 2772

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