Masons UNI PRO Flexible Air Barrier

Product Description

Masons UNI® PRO is a wall underlay and Flexible Air Barrier and is suitable for use as temporary weather protection to allow interior works to continue inside the building without the exterior wall cladding being fully in place for up to 150 days.

Once the cladding is in place, UNI® PRO becomes a secondary line of defence against moisture by ensuring moisture that occasionally penetrates the wall cladding is directed back to the exterior of the building.



  • Eliminates expensive delays due to hold-ups on cladding or bad weather 
  • Once installed, UNI® PRO works as a secondary line of defence against moisture over the life of the building, whilst still being highly breathable, passing vapour from the inside of the building out.
  • A fraction of the cost of rigid air barriers (materials and labour) whilst having most of the benefits
  • Much thicker and stronger than standard building paper/wrap 
  • Quick and easy installation



  • UNI® PRO is a non-woven, absorbent, water-resistant, synthetic wall underlay.
  • UNI® PRO is water-resistant and designed to provide temporary protection from weather conditions and UV exposure to timber framing, without the installation of the cladding, which allows for the continuation of internal work on the build for 150 days after installation. 
  • UNI® PRO comprises three polypropylene layers: two outer layers of non-woven polypropylene with a middle layer of a functional-technical film.
  • UNI® PRO has a blue front face and a white rear face - and a middle membrane which is dark grey. Both sides of the sheet have a fine embossing pattern. The sheet is 2.74 metres wide and marked "UNI® PRO Flexible Air Barrier


  1. Masons UNI® PRO Flexible Air Barrier is certified for use as a wall underlay and air barrier on buildings:a) within the scope limitations of:
    i. NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area for timber-framed construction; or
    ii. NZBC Acceptable Solution E2/AS4 with regards to building height and floor plan area for light-steel framed construction, and
    b) situated in wind zones (as defined in NZS 3604:2011) up to and including ‘Extra High’, provided stud and fixing centres are no greater than specified in the Masons UNI® PRO Flexible Air Barrier Design and Installation Guide V1.0, November 2021, and
    c) with absorbent or non-absorbent wall claddings directly fixed to the frame, or installed over an 18mm minimum drained cavity; or with masonry veneer, in accordance with NZBC Acceptable Solution E2/AS1 for timber-framed buildings or NZBC Acceptable Solution E2/AS4 for steel-framed buildings, and
    d) where the underlay is not exposed to view in an occupied space.
  2. Masons UNI® PRO Flexible Air Barrier shall be:a) installed in accordance with the MASONS UNI® PRO Flexible Air Barrier Design and Installation Guide V1.0, November 2021, and
    b) separated from fireplaces, heating appliances, flues and chimneys in accordance with the requirements of NZBC Acceptable Solutions C/AS1 and C/AS2, Paragraph 7.5.9 for the protection of combustible materials, and
    c) protected from sunlight within 150 days
  3. Contribution to compliance with Building Code clause H1.3.1(b) is conditional on:a) the element incorporating UNI® PRO Flexible Air Barrier being part of the thermal envelope of the building, and
    b) horizontal and vertical laps being securely taped.



  • In locations with a wind design pressure (ULS) of up to and including 4.6 kPa (which includes all NZS 3604:2011 wind zones).
  • UNI® PRO is suitable for 'Very High' wind zones over rigid wall underlays.
  • In seismic zones up to and including seismic zone 3.
  • In all exposure zones.
  • Further than 1 m from a relevant boundary.



  • For commercial and residential construction.
  • Designed for use with all cladding systems.
  • Performs on timber and steel framed buildings.
  • As a temporary cladding for up to 150 days.
  • With buildings of all building heights, up to the permissible wind design pressure of 4.6 kPa.
  • With cladding and joinery that complies with the relevant provisions of the NZ Building Code for the site and location.
  • Suitable for use as a non-rigid backing for stucco plaster.
  • UNI® PRO is suitable as an air barrier on walls that are not lined.
  • For vertical use only, not suitable as a roof underlay.
  • UNI® PRO Must be covered with a suitable wall lining to any occupied spacings.



  • UNI® PRO (or any flexible air barrier) cannot provide seismic (bracing or racking), and fire-resistance. 
  • For lightweight steel, a thermal wrap must be installed.
  • Where a building height is greater than 10 m and upper levels contain sleeping uses or other property the external wall must be subject to specific fire engineering.
  • In occupied spaces, UNI PRO must always be installed in conjunction with an internal lining.
  • UNI PRO must be covered within 150 days from installation.



  • UNI® PRO meets or exceeds the requirements of the NZBC.
  • Codemark Certified

If designed, installed and maintained in accordance with all Masons Plastabrick’s requirements, the UNI PRO will comply with or contribute to compliance with the following performance claims:

  • B2 Durability: B2.3.1(a), B2.3.2
  • E2 External moisture: E2.3.2 (contributes to), E2.3.5 (contributes to), E2.3.7
  • F2 Hazardous building materials: F2.3.1
  • H1 Energy efficiency: H1.3.1(b) (contributes to)



Masons UNI® PRO is to be installed with the correct components: 

Collectively these products complete the weather-tightness of the building membrane. 

General Installation Instructions:

UNI PRO must be installed by a Licensed Building Practitioner using Mason's full installation instructions.These instructions are available in the downloads button of this web page.
Training on-site can also be arranged via your Masons Rep.



Masons UNI® PRO, whether on or off-site should:

  • Be stored on end under a cover, in a clean and dry area 
  • Protect the rolls from crushing or damage
  • When fixing the product in windy conditions, care must be taken due to the large sail area created by wide roll widths


Masons Building Products has been in the industry for over 20 years. Customer satisfaction is paramount. A dedicated team of Masons Representatives cover NZ nationwide to assist and instruct customers in using Masons products. To contact your local Rep visit here