In 2014 Celotex supplied PIR insulation known as RS5000, through distributors, which was one of the components used in the Grenfell Tower rainscreen cladding system. Celotex does not design or install cladding systems and did not do so at Grenfell Tower.

In the days immediately after the fire Celotex discontinued the sale of RS5000 on a precautionary basis. Celotex subsequently also made the decision not to supply any insulation product for use in rainscreen cladding systems on buildings over 18 metres.

A second Celotex PIR insulation product, TB4000, was supplied through third-party distributors and was found on Grenfell Tower. TB4000 is a general-purpose insulation product.