The UNI System

UNI is a heavy 3 ply polypropylene flexible air barrier. Uni is highly resistant to air and liquid water whilst allowing water vapour to pass. UNI is substantially thicker than conventional flexible wall underlay and is very tough & strong. It is UV resistant for up to 90 days.

When assembled using specific components and according to the designated system UNI may be used as Flexible Air Barrier as a temporary weather protection allowing interior works to continue without cladding in place for 90- 150 days. UNI, UNI PLUS & UNI PRO carry Codemark certificates of conformity.

No, UNI PLUS is the fire retadant UNI Product

Ideally not. If longer UV resistance is needed UNI PRO is the UNI product to use, UNI PRO offers 150 days UV resistance. Very short over exposure – contact Masons for advice. Substantial over exposure will require an over wrap or re wrap in most cases.

No only cap nails or nailed battens may be used to fix UNI to timber frames, there cap screws for fixing to Steel frames. Staples may be used inside joinery opening and above the soffit framing line.

No this is an optional part or the system, this is up to the builder if they wish to use it to suit their build.

Only 40 Below Platinum or Flex have been tested and incorporated into the Codemark

Yes – flash all overlaps with 40 Below Platinum or Flex 75mm

Flash the sill & 200 mm up the jamb, flash the Head and Jamb 200 x 200 mm per Masons 40 Below Platinum or Flex, or UNI  installation instructions.

These vary with the stud spacing & the wind zones- check the Masons UNI installation instructions FIXING CHART for details.

For 600 mm studs with a 18-25 mm drained cavity YES to avoid the possibility of UNI billowing into the cavity if the insulation is over-pressed in.

If UNI is pulled TIGHT across the studs wrap strap should not be necessary. Some BCAs will insist on wrap strap being fitted over UNI as this is stated in E2/AS1. Over vigorous fitting of insulation may cause billowing.

If UNI is pulled and fitted TIGHT across the studs there should be no issue.

No, simply drape UNI 50 mm below the bottom plate until the cladding is in place

Yes with limitations. Studs and fixings need to be at stated intervals, and additional installation requirements apply per the Masons installation instructions. If the job is multi-storey or complex Masons Barricade Weather Defense rigid wall underlay system may be a more suitable choice.

Continuous timber or castellated battens may be used. Fastened per Masons installation instructions – UNI FIXING CHART.  James Hardie CLD battens TM may also be used for vertical batten applications. These must be fitted strictly in accordance with James Hardie installation instructions including fixings and intervals for CLD Battens TM NOT per the UNI Installation instructions UNI fixing chart.

Other types of battens have not been considered by Masons.

Additional flashing – weather deflectors and a second layer of UNI over the head flashing must be fitted for UNI or UNI plus used in Very High or Extra High wind zones. And for all wind zones when used for UNI PRO. Please see Masons UNI installation instructions and the Masons UNI & UNI PRO 10 min YouTube training videos. Masons recommend this method for all wind zones but is optional for UNI and UNI PLUS below Very High wind zones.

Yes, every effort should be made to use Masons Penetration seals.

If these genuinely cannot be obtained, then any trade seal based on acrylic adhesive and either BRANZ appraised, or Code marked may be used. Penetrations with a difficult shape (like HIVAC ducts, or brackets for pergolas, etc) may be flashed to the UNI with 40 Below Platinum or Flex working from the bottom of the penetration up the sides and finishing with the top – so water always runs off freely.