A1 Non-Combustible EWI System

The first non-combustible EWI system in Europe. First system certified A1.

Introducing a  breakthrough EWI system achieving an A1 non-combustible fire rating.

This is the first A1 rated fireproof insulation solution to be launched in the UK for building facades, exclusively available from Wetherby. The A1 System sets new standards in external wall insulation fire performance.

The vast majority of Mineral Wool systems in the UK achieve an A2 limited-combustible fire rating. This new innovative A1 system comprises of  reinforcing mesh and a non-

combustible basecoat to achieve the highest possible European fire classification to the BS EN 13501-1 standard.

The thermal benefit of the system is provided by the Wetherby A1 Stone Wool Insulation which is coated in the purely mineral Wetherby K&A A1 Scrim Adhesive. This is based predominantly on mineral and non-combustible raw material such as quartz, limestone, cement and lime, which ensures perfect adhesion between substrates and insulation board.


The system is finished with Wetherby Heck ED Mineral Render finishing coat, which is ideal for use with stone wool insulation, providing great breath-ability.


To achieve an A1 rating, the system must be classified to BS EN 13501-1 using the following fire tests. f

  • EN 13823 SBI (Single Burning Item) – Used to determine the reaction to fire by exposing a flame to the system finish.
  • BS EN ISO 1716:2010 – Bomb test. Each component of the system is ‘blown up’ to measure heat output (calorific value). All components must be A1.

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