Thermoseal Group Limited

Thermoseal Group Limited manufactures and supplies components and machinery for insulating glass unit (IGU) production. Its range includes warm-edge spacer systems, spacer bars and accessories, sealants, molecular sieve desiccants, Georgian and Victorian decorative systems, tapes, tools and IG manufacturing equipment. The company serves insulating glass manufacturers and the wider window and glazing industry in the UK and international markets, including North America. Its Thermobar and Thermoflex warm-edge spacer systems are designed to improve the thermal performance of windows. Thermoseal combines in-house manufacturing, product development and testing with a range of more than 2,500 IG components. Since 2024, it has been part of Fenzi Group.

Thermobar — rigid warm-edge spacer system;
Thermoflex — flexible silicone-foam warm-edge spacer system;
DecraLed — decorative adhesive lead, films, bevels and related decorative-glass products.

The business was founded in 1979, initially manufacturing hopper-fed hot-melt extruders.