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Appraisal number: 473 (2017)

Date issued: 17 Jan 2018

ARDEX Undertile External Liquid Waterproofing Membranes


ARDEX Undertile Liquid Membranes are liquid-applied waterproofing membranes for use under ceramic or stone tile finishes on external decks and balconies.


ARDEX Undertile Liquid Membranes have been appraised for use as deck and balcony waterproofing membranes for buildings within the following scope:

  • The scope limitations of NZBC Acceptable Solution E2/AS1 paragraph 1.1.
  • The scope limitations of NZBC Acceptable Solution E2/AS1 paragraph 1.1 with regards to building height and floor plan area when subject to specific engineering design.
  • With substrates of fibre-cement compressed sheet or suspended concrete slab.
  • With minimum falls for fibre-cement compressed sheet of 1:40 or suspended concrete slab of 1:60.
  • With deck and balcony size limited to 40 m².
  • Situated in NZS 3604 wind zones up to and including extra high.

Decks and balconies must be designed and constructed in accordance with the following limitations:

  • With the membrane continually protected from exposure to ultraviolet (UV) light and from physical damage by ceramic or stone tile finishes.
  • With no steps within the deck level and no downpipes discharging directly onto the deck.

Movement and control joints in the substrate must be carried through the membrane and tile finish. The design and construction of the substrate and movement and control joints is specific to each building and is 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 ARDEX New Zealand Ltd.

Technical literature

  • ARDEX WPM 001 – Superflex Bathroom and Balcony Premix - 1 Part (NZ), March 2012
  • ARDEX WPM 002 – Superflex Bathroom and Balcony - 2 Part (NZ), March 2012
  • ARDEX WPM 155 Rapid (NZ and AUS), May 2013

Consenting instructions

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

Appraisal holder

ARDEX New Zealand Ltd
Phone: 09 636 0005

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