• Approved


  • Design
  • Manufacture


  • The Wetherby Building Systems Ltd. Modular Brick Slip & Silicone Rendered External Wall Insulation Systems

The Wetherby Building Systems Ltd. Modular Brick Slip & Silicone Rendered External Wall Insulation Systems

Durability Assessment – 60 Years

System Description

The system comprises white tongue and groove edge profile EPS insulation boards, which are mechanically fixed through galvanised steel top-hat section or treated timber batten vertical spacer support rails using approved Wetherby mechanical fixings, to form a drained and partially ventilated minimum 15mm wide cavity between the structural wall and the EPS insulation boards. The fixing of the spacers to the structure can be non-stainless steel corrosion protected fixings. The fixing of the insulation to the supporting structure is to be by means of stainless steel fixings of centre pin Grade 1.4301 and plastic anchor sleeve material such as polyamide (PA6 and PA6.6), polyethylene (PE), polypropylene (PP) or, stainless steel Grade 1.4301. Fixings must be installed at the horizontal and vertical centres specified by Wetherby for the project-specific conditions. The base track must be stainless steel Grade 1.4301.

Limits of Scope

  • Maximum height and distance from boundaries for each system must meet the requirements of the Building Regulations within the United Kingdom in force at the time of construction, that is, the current edition + amendments of Approved Document B Volumes 1 & 2 in England, Approved Document B Volumes 1 & 2 in Wales, Domestic Technical Handbook Section 2 and Non-domestic Technical Handbook Section 2 in Scotland, and Technical Booklet E in Northern Ireland.
  • Bottom of the cladding must be a minimum 150mm above external ground level;
  • A minimum 15mm ventilated and drained cavity must be maintained behind the insulation board;
  • Risk of interstitial condensation within external elements subject to site-specificassessment.
  • A detailed maintenance plan must be prepared and provided to the building manager/owner on completion. As a minimum, this should include an inspection for evidence of defects twelve months after the application, and subsequently every five years;
  • The structural elements (not part of this assessment) must be designed by a chartered structural engineer experienced in this type of structure taking into account the anticipated cladding loadings;
  • The design of the cladding system must take in to account the wind loads attributable to the geographical location of the site in terms of wind loading, deflection, and resistance to pull-out of the fixings;
  • Wetherby Building Systems Ltd. must be contracted for the design, manufacture and supply of the cladding system;
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