Product Filters

  • Manufacturer

  • Material type

  • Thermal conductivity

  • Width

  • Thickness

Clear all

Celotex Thermaclass Cavity Wall 21

(3 Products)

Offering excellent thermal performance with a thermal conductivity of just 0.021 W/m.K, Celotex Thermaclass Cavity Wall 21 is the perfect insulant for cavity walls. The boards boast an engineered tongue and groove joint profile, ensuring a continuous layer of insulation and optimal thermal performance, as well as protection from wind-driven rain.

Find Out More About Our Types of Celotex Thermaclass Cavity Wall 21
Filter Products

Celotex Thermaclass Cavity Wall 21 is built with a high-performance polyisocyanurate (PIR) core, secured between two sheets of low-emissivity foil facing for superior thermal performance.

The PIR foam core is renowned for its excellent thermal insulation properties, while the low emissivity foil facings provide a reflective surface that helps to reduce heat loss and maximise thermal performance.

The BBA has verified that Thermaclass Cavity Wall 21 is an ideal insulant for full fill cavity wall applications, provided it is installed and maintained in accordance with the certificate's instructions.

Offering high flexibility, this product can be installed with either a 10mm residual cavity for easy installation and mortar squeezing, or as an entirely full-fill solution without any residual gaps whatsoever.

Please Note - Due to safety regulations, Thermaclass Cavity Wall 21 should not be employed in the external walls of buildings exceeding a height of 18 meters (England and Wales) or 11 meters (Scotland).

Celotex Thermaclass Cavity Wall 21 Key Features:

Celotex Thermaclass Cavity Wall 21 has several features that make it an excellent choice for cavity wall insulation. These features include:

  • High Thermal Performance: This insulation board has a thermal conductivity of 0.021 W/mK and provides improved thermal performance in sealed cavity air spaces, while reducing the thickness of insulation required to hit the target U-value
  • Easy To Install: Whether you choose to install Thermaclass 21 with a 10mm residual cavity to accommodate mortar squeeze, or as full fill cavity insulation, this product offers ultimate flexibility. 
  • BBA Approved – Certificate 16/5343 (Full Fill Cavity Walls).
  • Fire-Rating: Euroclass E Reaction to Fire classification, according to BS EN 13501-1. 
  • Environmentally Friendly: This high thermal performance polyisocyanurate (PIR) insulation board is manufactured using a blowing agent that has a low global warming potential, making it an eco-friendly choice.

Frequently Asked Celotex Thermaclass Cavity Wall 21 Questions

All Categories