StoTherm Insulated Facade System
- Appraisal number 478
- Valid from
- Information provider
- BRANZ Limited
- Information type
- BRANZ Appraisal
The StoTherm Insulated Facade System is a cavity-based Exterior Insulation and Finishing System (EIFS) wall cladding. It is designed to be used as an external cladding system for residential and light commercial type buildings where domestic construction techniques are used.
The StoTherm Insulated Facade System consists of StoTherm or StoTherm+ expanded polystyrene (EPS) panels fixed over polystyrene battens to form the cavity. The coating system consists of a nominal 5 mm thick cement-based render applied to the polystyrene panels, an approximate 2.5 mm thick coat of fibreglass mesh reinforced synthetic resin render (StoArmat render system only), and an approximate 1-3 mm thick coat of coloured finishing render. The render system is finished with a Sto coating.
The system incorporates a primary and secondary means of weather resistance (first and second line of defence) against water penetration by separating the cladding from the external wall framing with a nominal 20 mm wide cavity. The cavity allows for any occasional ingress of water that may get past the external skin to drain to the exterior of the building, and any remaining moisture to dry by evaporation.
The StoTherm Insulated Facade System has been appraised as external wall cladding systems for buildings within the following scope:
- the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1; and,
- with a risk score of 0-20, calculated in accordance with NZBC Acceptable Solution E2/AS1, Table 2; and,
- situated in NZS 3604 Wind Zones up to, and including Extra High.
The StoTherm Insulated Facade System has also been appraised for weathertightness and structural wind loading when used as an external wall cladding system for buildings within the following scope:
- the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area;
- constructed with timber and steel framing subject to specific engineering design; and,
- situated in specific design wind pressures up to a maximum design differential ultimate limit state (ULS) of 2.5 kPa.
The StoTherm Insulated Facade System must only be installed on vertical surfaces (except for tops of parapets, sills and balustrades, which must have a minimum 10o slope and be waterproofed in accordance with the Technical Literature).
The system is appraised for use with aluminium windows and door joinery that is installed with vertical jambs and horizontal heads and sills. (The Appraisal of the StoTherm Insulated Facade System relies on the joinery meeting the requirements of NZS 4211 for the relevant Wind Zone or wind pressure.)
Installation of components and accessories supplied by Stoanz Limited and Sto registered contractors must be carried out only by Sto registered contractors.