Epsitec Stone Wool Insulation Systems - PS4 & PS5

Manufacturer guidance

The systems can improve the thermal performance of external walls and can contribute to satisfying the requirements of the National Building Regulations. For further information please visit the system’s BBA Certificate.

Manufacturer guidance

Ensure the substrate is clean and structurally sound. The substrate must be completely dry and not damaged by rain or frost. Consult the board manufacturer and redo pull-out tests before continuing if rain or frost damage is evident.

Sheathing boards must achieve minimum pull out requirements to be suitable for the system application. Ensure sheathing boards or panel substrates are line and level to allow RagRails to be installed flush to the substrate. Slight variances in the substrate can be overcome by using suitable packers to ensure the system is installed line and level. All sheathing boards must be securely fixed correctly jointed and sealed (where required) as per the board manufacturer's instructions.

If the walls are not line and level, the fixing lengths must be checked to ensure adequate embedment into the sheathing board / frame substrate. This will need to be confirmed on site prior to the installation of the Wetherby system. Sizing of flashings trims and beads may also require alterations.

Existing timber or steel cladding - remove any defective areas of the existing substrate and where required make repairs ensuring the surface is ready to receive the EWI system. The existing walls are to be cleaned to the satisfaction of the Contract Administrator to remove any friable material algae or lichen. WBS Biocidal Wash can be used to treat areas of moss algae and mould growth.

Manufacturer guidance

The RagRails or timber battens help to create a drainage cavity between the sheathed frame and external wall insulation. This cavity will then allow for any moisture located within these areas to track down and drain out, either from the bottom of the system or into specifically designed drainage boxes.

Manufacturer guidance

The fixings of the rails or battens will need to be appropriate for the substrate that the system will be installed over. Fixings and the frequency of them will be subject to pull out tests and wind load calculations. 

Manufacturer guidance

The stone wool insulation boards are mechanically fixed with WBS approved fixings, combined with a suitable washer. The fixings frequency, type and length are subject pull-out tests and wind load calculations. 

Manufacturer guidance

Fixing type, length and frequency all subject to pull out tests, job specific detailing/requirements and wind load calculations. Contact manufacturer for further information.

Manufacturer guidance

All structural movement joints must be mirrored through the EWI System. As a minimum, incorporate the movement joints every 7–10 m vertically and at every other floor level horizontally. Structural Engineers will be required to confirm how much movement will occur and where movement joints are located in the substrate.

Manufacturer guidance

50 m² roll.

Manufacturer guidance

Secondary mechanical fixings are required on all projects two storeys and above at a rate of 1 per m² as per BRE Report BR135:2013. NHBC require in all cases that a minimum of one non-combustible fixing is installed through the reinforcement mesh per insulation board, in addition to other fixings.

Manufacturer guidance

Any NCS or RAL reference. Insert requirements.

Manufacturer guidance

The manufacturer offers a product sample service, providing a small sample of the finished build-up, colour and texture before a final decision is made. Contact the manufacturer for further information.