Celotex is the UK’s leading manufacturer of high performance PIR thermal insulation boards. Celotex is the UK’s leading manufacturer of high performance PIR thermal insulation boards. As such, when you choose Celotex insulation, you are accessing an unrivalled product and service package that has evolved through a process of constant innovation spanning eight decades. The evolution continues with intensive product development to ensure that our product range provides thermal insulation solutions that meet the requirements of current legislation as well as the demands of building professionals, specifiers and users. These developments are represented in our depth of product offer; our range encompasses the thinnest and thickest boards available to the construction industry, with boards from 12mm to 200mm thick available from stock. As an innovator within the insulation sector, Celotex is committed to an extensive programme of research and development. All of the company’s products are manufactured at its plant and HQ in Suffolk. Celotex: we know insulation inside and out.