NBS Source

Epsibrick External Wall Insulation System - PS2

Verified by manufacturer 25 days ago

Wetherby Building Systems Ltd Third party certifications:
  • BBA Agrément Certificate

    BBA Agrément Certificate

    Certificate type

A masonry BBA certified system consisting of a mineral wool insulation board, basecoated, meshed, finished off with brick slip finish.

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Suitable for use on the outside of external masonry walls of new or existing domestic and non-domestic buildings, with height and boundary restrictions (see systems BBA certificate for further information).


The Epsibrick External Wall Insulation System, comprising mechanically fixed mineral wool (Stone Wool) insulation boards, with supplementary adhesive (minimum 40%), a reinforced basecoat, and brick slip finish.

General information


See Brick Slip Brochure.



Ten year


Ss_25_45_72_28 External wall insulation systemsPrimary


M21/20 External wall insulation system . . . . . .

M21/210 External wall insulation system

Specification data - External wall insulation systems

System performance

Thermal Performance.

The systems can improve the thermal performance of external walls and can contribute to satisfying the requirements of the National Building Regulations.

Strength and Stability.

The systems can adequately resist wind loads and impact damage.

System Tested to BS EN 13501-1:2007.

Achieved a value of A2-s1, d0 reaction to fire.

Risk of Condensation.

The system can contribute to a limiting risk of interstitial and surface condensation.


When installed and maintained in accordance with the Certificate holders recommendations and this Certificate, the system will remain effective for at least 30 years.

Further Information.

For further information on the above points please visit the system’s BBA Certificate.


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.

Support rails and brackets


Fixing method



WBS Aluminium Base Rail.

Securely fix Wetherby BSR starter track 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.

Bracket fixings

WBS HIT 6/5 Hammerscrew Bead Fixing.




Insulation Boards must be mechanically and adhesively fixed. Fixings specified are subject to pull out tests, wind load calculations and project requirements.

Stone Wool Insulation.

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


-              Board Size: 1200 x 600 mm.

-              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.

Insulation Boards can be mechanically and adhesively fixed or mechanical only. If a plastic pin fixing is used a minimum of 40% of bedding adhesive must be applied to the back of the boards. If a metal pin fixing is used then bedding adhesive will not be required. 

Additional mechanical fixings

The Stone Wool Insulation Boards are mechanically fixed with WBS approved fixings. Please contact Wetherby for further information on this. The fixings frequency, type and length would be subject Pull-Out Tests and Wind Load Calculations. 


T-FIX-8M Range.

T-FIX-8S Range.

Movement joints


Form with

All structural movement joints must be mirrored through the EWI System. As a minimum to 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. 

WBS Stainless Steel Movement Joints.

WBS PVC Movement Joints.

WBS Stainless Steel Surface Mounted Render Stop Beads.

WBS PVC Surface Mounted Render Stop Beads.


Compriband sealing tape installed between the insulation boards.

Render carrier or reinforcement



Glass fibre reinforcement mesh incorporated into scrim adhesive.

Mesh size


50 m².


Secondary mechanical fixings are required on all projects 2 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. Install secondary fixings through the first pass of wet scrim adhesive and WBS Alkali Resistant Scrim Cloth. 100 x 100 mm scrim patches to be installed over each secondary fixing head. All fixing types, lengths and frequency subject to pull out tests and wind load calculations. Finally scratch scrim adhesive horizontally in preparation for the Wetherby 7–15 mm Brick Slips.

TID-MR Range.

DHM Range.




Brick Slip Adhesive.

Trowel apply full spread of Brick Slip Adhesive to the scrim adhesive. Use a 10 mm notched trowel to ensure minimum 5 mm thickness is achieved.

Decorative finish

WBS Pointing Mortar.

Once brick slips have set, point up with WBS Pointing Mortar using a pointing gun. Shape mortar to desired joint type using a pointing trowel. Care should be taken not to apply WBS Pointing Mortar onto the brick slip face or pistols as this can be very difficult to remove. Once pointing mortar is dry, brush down the wall to remove all loose mortar etc.

WBS 7–15 mm Brick Slips.

WBS Brick Slips should be cleaned before application ensuring all slips are free of residue. Whilst the brick slip adhesive is wet the brick slips can be firmly pushed into the adhesive. Brick slips should be installed line and level and staggered leaving a consistent joint.

NB. Brick Slips are manufactured using raw natural ceramics and will inevitably vary in nature. Natural variations in colour, texture and dimensions may be present. It is advisable to mix slips from at least 5 boxes to minimise grouping of colours. Any product deemed faulty or out of tolerance should not be applied and should be reported to Wetherby immediately. 


See Brick Slip Brochure.

System accessories

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

WBS Firtree Fixings.

WBS Jointing Pieces.

WBS End Caps.

WBS EVO-STIK Silicone Sealant.

Samples required

Submit samples of Wetherby Brick Slips 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 brick slip type before a final decision is made. Contact the manufacturer for further information.

System completion

Inspection of completed installation.

Documentation for insulated render systems.

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

BIM objects

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Platform Compatible Version




Third party certifications

BBA Agrément Certificate

BBA Agrément Certificate

EpsiBrick Mineral Wool External Wall Insulation System 14/5137 - PS2

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