Masons UNI FAB. It’s a game changer!

Written by


09 August 2021


2 min read


Masons is an innovative importer and nationwide distributor of building products, wholly New Zealand owned and operated. One of our most innovative products is the Masons Uni, or Uni ‘FAB’.

But what is a ‘FAB’, or ‘flexible air barrier’? and why would you use a ‘flexible air barrier’?

In technical terms it is a non-woven, water-resistant, breathable 180gsm synthetic wall underlay, with up to 90 days UV exposure. But what does that mean to the standard person in the building industry, or to the homeowner and developer?

Well, a ‘FAB’ (flexible air barrier) in terms of overall performance and function sits between a normal building paper/wrap, and a rigid wall underlay or air barrier.

Masons Uni is much thicker and stronger than standard building paper/wrap and so it can provide some of the same benefits as a rigid wall underlay or air barrier can.

When Masons Uni is installed with the correct components such as 40 Below window-flashing tapes which ensure weather-tightness around windows and joinery, Uni cap nails to an engineer specified fixing pattern which ensure wind-loading up to ‘Very High’ and the Uni Seam Tape and Masons Penetration Seals that complete the weather-tightness of the building membrane.

There are only two functions that Masons Uni (or any flexible air barrier) cannot provide which a rigid wall underlay or air barrier does: seismic (bracing or racking), and fire-resistance.

This leads us back to the ‘why would you use a flexible air barrier’ question. Well, because Masons Uni performs as an air barrier, once the Uni is installed work can continue on the inside of the building for up to 90 days without waiting for the cladding to be installed. This means Masons Uni provides early enclosure of the building.

This is an enormous cost saving to the overall build as work can continue inside. And while Uni may be about twice the price of standard building paper/wrap, it is a fraction of the price of a rigid wall underlay or air barrier.

However, once the cladding has been installed, Masons Uni also works as a secondary line of defence against moisture over the life of the building, while still being highly breathable, passing vapour from the inside of the building out.

Masons Uni FAB (flexible air barrier) is quite literally, a game-changer!

For further information on UNI FAB call 0800 522 533 or visit

Masons UNI FAB. It’s a game changer!