Pro Clima’s new façade systems bring weather, thermal and movement performance together

As building envelopes become more complex, the conventional combination of insulation between framing and a mechanically fixed flexible underlay is being pushed beyond the conditions for which it was typically designed.

Higher wind pressures, structural movement and increasingly demanding thermal requirements mean façades must manage weather, air leakage, moisture and heat transfer as one coordinated assembly.

Pro Clima’s FORTX™ and FORTX™ MELIOR systems have been developed in response. Both use a fully adhered weather-resistive barrier applied directly to a rigid board substrate, creating a flat, continuously supported layer behind the cladding.

By removing the localised fixing points associated with loose-laid wraps, the approach helps reduce the ballooning, movement and fatigue that can occur under fluctuating wind pressure.

The FORTX™ assembly has been tested to AS/NZS 4284 as a standalone weatherisation layer, without cladding attached. Testing recorded a Serviceability Limit State of ±3.5kPa, an Ultimate Limit State of ±5.5kPa and air leakage below 0.1L/s/m².

This allows the weather-resistive layer to be assessed independently from the final façade finish, potentially giving architects greater flexibility when working with different cladding materials and support systems. It can also allow the building to be enclosed earlier, helping internal work progress while cladding installation continues.

FORTX™ can be formed using SOLITEX EXTASANA ADHERO®, a Class 3 vapour-permeable weather-resistive barrier, or SOLITEX® ADHERO FC, a Class 4 alternative. When combined with INTELLO® PLUS internally, the assembly also supports airtightness and moisture control through the full depth of the wall.

FORTX™ MELIOR extends this approach by introducing a continuous external layer of non-combustible ROCKWOOL™ Rainscreen™ stone wool insulation.

Positioning insulation outside the primary structure helps reduce the thermal bridging created by timber or metal framing. In one steel-stud wall example supplied by Pro Clima, adding 50mm of external ROCKWOOL™ insulation increased the total system performance from R1.40 to R2.85.

This creates what is often described as a “warm structure”, moving the dew point outward and helping the rigid board and framing remain warmer and drier. The dense stone wool layer also contributes to acoustic performance and fire safety, with ROCKWOOL™ Rainscreen™ classified as non-combustible to AS 1530.1.

Structural movement is addressed through TFLEX, a vapour-permeable flexible control-joint material designed for seismic joints and inter-storey transitions. The tested system accommodates movement of ±20mm at SLS and ±75mm at ULS.

Together, these elements allow weather protection, airtightness, thermal performance, moisture management and structural movement to be considered as one façade strategy rather than a collection of separate products.

To introduce the systems in practice, Pro Clima is holding free three-hour FORTX™ Façade Systems workshops in Auckland on 15 and 16 October, and Christchurch on 21 and 22 October.

The sessions will cover building science, testing, NZBC compliance and façade detailing before moving into hands-on installation using weather-resistive barriers, insulation, windows, fire barriers, façade clips and thermal breaks. Attendees can earn 30 NZRAB CPD points or three LBP points.