Epsicon 3 - External Wall Insulation System - PS3 - External Wall Insulation Dash Finish

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. Treat areas of moss, algae and mould growth with WBS Biocidal Wash. Dense smooth surfaces may require treating with WBS Stabilising Solution / Bonding Agent to ensure adequate adhesion on wet fix or render only applications. 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 / defective areas to leave a suitable surface for the application of the insulation boards. Maximum dubbing coat thickness: 16mm. 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. Where required, apply one coat of Wetherby Stabilising Solution to the entire surface by roller, ensuring uniform coverage and allow to dry.

WBS Powder Coated Galvanised Steel Bellcast Bead.

Guidance for specification option:

Securely fix Wetherby bellcast bead above DPC level at base of the system. Mechanically fix bellcast bead at max. 300mm centres, 50mm from each end. Packing shims may be required to ensure the Bellcast bead 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.

Stone Wool Insulation.

Guidance for specification option:

Thermal Performance Ranging from 0.036, Thicknesses compatible with the system’s certification range between 80mm – 250mm.

-              Board Size: 1200 x 600mm.

-              Minimum Compressive Strength: 10 kPa.

-              Thermal Conductivity: 0.036 Wm²/K.

-              Performance in Relation to Fire:

-              Class A1 (BS EN 13501-1:2002).

-              Non-combustible.

-              Environmental:

-              CFC / HCFC Free.

-              Zero ODP.

-              GWP Less Than 5 

WBS Insulation Bedding Adhesive (minimum 40%).

Guidance for specification option:

WBS Bedding Adhesive should be applied in a continuous line around the perimeter of the board with 3 additional dabs of adhesive distributed uniformly over the remaining surface. At least 40% of the board should be covered. The boards should be fully bedded into the adhesive and a mechanical fixing installed through the centre of each board to hold in place whilst the adhesive dries. Alternatively, apply WBS Insulation Bedding Adhesive to the entire face of the insulation boards using a 10mm minimum notched trowel ensuring a full spread of adhesive.

Compriband sealing tape installed between the insulation boards

Glass fibre reinforcement mesh incorporated into scrim adhesive.

50 m² Roll.

WBS Polymer Cement Dashing Mortar.

Guidance for specification option:

Trowel apply one coat of WBS Polymer Cement Dashing Mortar in the traditional manner, at a thickness of 8-10mm. A darby or straight edged tool may be used to ensure a relatively uniform thickness, which can be smoothed out using a plastic float. Complete individual surfaces in one operation where practical.

WBS Mineral Aggregate Spar Dash.

Guidance for specification option:

Whilst the freshly applied Dashing Mortar is still wet, dry dash the render surface in an upwards motion using clean Wetherby dashing grade mineral aggregates. Ensure consistent application of the aggregate to leave an aesthetically pleasing finish. 

Please see Wetherby Through Coloured Render & Spar Dash Systems document for further information.

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

WBS Firtree Fixings.

WBS Jointing Pieces.

WBS End Caps.

WBS approved silicone sealant.

Submit samples of Wetherby Dash Finish for approval. Keep approved samples on site for the duration of the contract for inspection and comparison purposes. 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.

Install system as per manufacturer’s instructions.

Inspection of completed installation.

Documentation for insulated render systems.

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