Rainscreen Cladding
URSA WALLTEC BLACK and URSAPAN BLACK slabs are British Board of Agrément (BBA) approved for use behind rainscreen cladding systems, both new build and refurbishment. The slabs have a black glass fleece facing so they can be used in open joint cladding systems without being seen. URSAPAN slabs have a plain glass fleece facing.
Design
Rainscreen cladding is a lightweight, non-load bearing system attached to the outside of a building using a bracket and rail system. It provides protection from wind and rain, improves the thermal performance and limits solar gains, with a ventilated void – typically 50mm – behind the cladding keeping the system dry. A wide range of external finishes are available, from plain and coloured metals, embossed metal and terracotta to fibre reinforced cement sheet, natural and artificial stone and more.
Some systems also offer a traditional brick or block outer leaf with a 50mm clear residual cavity; these have special wall tie systems that use restraint channels and matching ties.
Thermal
Rainscreen cladding systems may be used in both new build and refurbishment schemes in order to achieve the required U-value.
URSA WALLTEC BLACK 32 has a thermal conductivity of 0.032 W/mK while URSAPAN BLACK has a thermal conductivity of 0.035 W/mK, both products providing a continuous envelope of insulation around the building.
The ventilated cavity and external insulation protect the building from summer overheating whilst during the heating season advantage can be taken of the high thermal mass of concrete framed buildings.
Fire
URSAPAN BLACK, URSAPAN & URSA WALLTEC BLACK 32 are deemed non-combustible with a fire classification of Euroclass A1 (the highest possible rating) when tested to EN 13501-1:2018 Reaction to Fire.
The ventilated cavity behind the cladding system means cavity barriers are needed to prevent the spread of fire and/or smoke. Horizontal cavity barriers should be installed at floor level and at roof level, and if required a vertical barrier should be added to further sub-divide the cavity at compartment walls. Details can be found in Approved Document B (England & Wales) and the Fire Section of the Technical Handbooks (Scotland). Similarly, all openings should be correctly fire stopped to prevent a fire from inside the building being able to break into the cavity.
The Approved Document B for England & Wales requires insulation products in high rise cladding systems (11 metres or higher) to be of ‘limited combustibility’ or better, and in Scotland the insulation should be totally ‘non-combustible’.
The cavity barriers should also be ‘non-combustible’, penetrate the full depth of the wall insulation and be securely fixed to the main structural wall. If they’re in a ventilated rainscreen cladding system, they should also incorporate an intumescent strip to fully close the cavity in the event of a fire.
Installation
Download the detailed installation guide here
Download a copy of the British Board of Agrément (BBA) certificates below:
Smugglers Way, Wandsworth case study and typcial install here.
Heat Loss Calculations
For more information and U-values, download our technical brochure here
We can also undertake 3D thermal modelling to accurately show the effect of the brackets on the overall U-value in rainscreen cladding systems. Please contact URSA Technical Services.