HECK ETA 18_0229 - Stone Wool, Silicone Render (A2) and Mineral Render (A1)

Reaction to fire classification to BS EN 13501-1, A2-s1, d0. Design life duration (minimum): 25 years.

Guidance for specification option:

This system can achieve an A2-s1, d0 reaction to fire classification for Silicone Render System. A1 Mineral Render System achieves an A1 reaction to fire classification please contact Wetherby Building Systems for further information on this.

When installed and maintained in accordance with the Certificate holders recommendations and this Certificate, the system will remain effective for at least 25 years.

Ensure surfaces are sound, free from loose material and clean.

Guidance for specification option:

Remove any loose material and existing render, where required dub out the surface level, ready to receive the EWI system. The existing walls are to be cleaned with a wire brush or pressure jet wash, to the satisfaction of the Contract Administrator, to remove any friable material, algae or lichen, and to provide a good key for Wetherby products. 

Wetherby Dubbing Render.

Guidance for specification option:

Where necessary dub out any hollow or defective areas to leave a suitable surface for the application of the insulation boards. Maximum coat thickness 16 mm.

If the walls include existing render or the substrate isn’t line and level and requires dubbing out, the fixing lengths stated within this specification may need to change. 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. Where necessary dub out, using Wetherby Dubbing Render, any hollow or defective areas to leave a suitable surface for the application of the insulation boards.

WBS Biocidal Wash.

Guidance for specification option:

Treat areas of moss, algae and mould growth with WBS Biocidal Wash.

Where required, apply one coat of Wetherby Biocidal Wash to the entire surface by roller or knapsack spray and allow to dry. Brush the surface to remove all signs of growth before rendering commences.

WBS Stabilising Solution.

Guidance for specification option:

Dense smooth surfaces may require treating with WBS Stabilising Solution / Bonding Agent to ensure adequate adhesion on wet fix or render only applications.

Where required, apply one coat of Wetherby Stabilising Solution to the entire surface by roller, ensuring uniform coverage and allow to dry.

WBS Aluminium Base Rail.

Guidance for specification option:

Securely fix Wetherby starter track with profile clip above DPC level at base of the system. Mechanically fix starter track at max. 300 mm centres, 50 mm from each end. WBS 3756 base rail connectors should be used to join the tracks, packing shims may be required to ensure the starter track is true to line and level. Any gaps behind the basetrack allowing free air movement behind the insulation should be sealed appropriately.

WBS HIT 6/5 Hammerscrew Bead Fixing.

WBS Insulation Bedding Adhesive.

Compriband sealing tape must be installed between the insulation boards.

Glass fibre reinforcement mesh incorporated into scrim adhesive.

Heck Silicone Primer.

Heck Silicone Render Finish.

Guidance for specification option:

Mix and apply Wetherby Silicone Textured Finish strictly in accordance with the manufacturer’s printed instructions. The top coat should be applied with a stainless steel trowel to the thickness of the grain and finished with a plastic float. Apply in a continuous application always working to a wet edge and in the same direction to ensure consistency of finish. Wherever possible, entire elevations should be completed in a single operation to avoid joint marks in the finish. This can often be achieved by working to natural breaks in the building or working to breaks in colour or texture.

Do not apply Wetherby Silicone Textured Finish with differing batch numbers on the same elevation. Care should be taken to avoid texture changes at different levels. Prior to setting, polish render with plastic float to give an even texture and remove all trowel marks.

WBS Heck ED Mineral Render Finish.

Guidance for specification option:

Mix and apply Heck ED Mineral Render Finish strictly in accordance with the manufacturer’s printed instructions. The top coat should be applied with a stainless-steel trowel to the thickness of the grain and finished with a plastic float. Apply in a continuous application always working to a wet edge and in the same direction to ensure consistency of finish. Wherever possible, entire elevations should be completed in a single operation to avoid joint marks in the finish. This can often be achieved by working to natural breaks in the building or working to breaks in colour or texture. Prior to setting, polish render with plastic float to give an even texture and remove all trowel marks. Allow the Mineral Render to fully dry.

WBS Silicone Paint (For the Heck ED Mineral Render Finish).

Guidance for specification option:

Apply two coats of WBS Silicone Paint to the WBS Heck ED Mineral Render using a roller or brush as per the printed manufacturer’s instructions.

Not required.

Aspira Render Protector.

Guidance for specification option:

Optional.

Apply Wetherby Aspira Render Protector with a roller ensuring a full and even coverage, covering 100% of the substrate. The substrate must be fully dry and clean before application; ensuring morning dew is not present on the substrate. Cross hatch application is recommended to ensure all areas are fully treated. Do not dilute product and protect from rain for a minimum 12 hours after application to allow coating to fully dry. 

WBS Sealing Tape: Pre-compressed, expanding waterproof sealing tape.

WBS Firtree Fixings.

WBS Jointing Pieces.

WBS End Caps.

WBS EVO-STIK Silicone Sealant.

WBS Fire Rated Silicone Sealant.

WBS APU Bead.

Submit samples of WBS Silicone/ Mineral Render for approval. Keep approved samples on site for the duration of the contract for inspection and comparison purposes.

Guidance for specification option:

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.

Inspection of completed installation

Documentation for insulated render systems

O&M manuals and data sheets relevant to the system installed