Celotex Insulation Boards

(34 products)

Celotex Insulation Boards are a versatile PIR insulation board popular that are made for a variety of uses, including Cavity Wall insulation, floor insulation and internal wall insulation. Celotex is a popular choice due to its DIY-friendly nature - being easily cut to size, with an ability to friction-fit between joists and studs, and are lightweight with a small form-factor, without sacrificing effective thermal insulation. 

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Frequently Asked Questions

What is Celotex PIR Insulation Board?

Celotex is a brand of Polyisocyanurate (PIR) insulation board - a type of rigid foam insulation board backed with a foil layer, ideal for its exceptional thermal performance. It is a strong and light type of foam insulation board that keeps structures warm by trapping air inside. PIR insulation is lightweight, durable, and offers excellent fire resistance and thermal insulating properties, making it a super DIY-friendly solution that can easily be cut to size to fit rafters, joists and stud walls, and used as Cavity Wall Insulation. We also sell a Celotex PIR Insulated Plasterboard which is ideal to save time in stud wall applications. 

What Sizes Do Celotex Insulation Boards Come in?

Standard Celotex insulation boards measure a standard size of - 2400mm x 1200mm, and are available in a variety of thicknesses to suit every size of floor, cavity or project such as:

25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 75mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 150mm and 200mm. 

The most popular sizes are 100mm Celotex, 50mm Celotex and 25mm Celotex. 

Celotex Cavity Wall Insulation Boards (CW4000) and Celotex Thermaclass Cavity Wall Boards have a narrower width of 450mm to make them easier to install in the construction of cavity walls.

Celotex Installation - How to Install

Due to it’s versatile nature, there are many different uses for Celotex Insulation and therefore many different ways to correctly install Celotex insulation. However, generally Celotex should be purchased to fit the depth of the cavity or space it is to fill other than when used as partial-fill insulation in cavity walls. It can be cut to size to fit the height and width of cavities, joists and rafters using a sharp utility knife or handsaw for thicker boards. It is typically designed to be friction-fit to a space, meaning the boards should fit tightly and stay easily in place with no additional fixtures and fittings.

For precise installation instructions for your specific use case, it is recommended to consult your builder, architect or building inspector to ensure installation complies with building regulations.