Classic Closures Multi-Cav

Multi-Cav Cavity Closures are manufactured from closed cell HCFC/ CFC free extruded polystyrene insulation and recycled UPVC extrusion. Resulting in an Ozone Depletion rating of Zero and a Global Warming Potential of 1. Multi-Cav provides a simple low cost, effective One Piece Solution for closing cavities around window and door openings in new masonry walls.

Water resistant properties prevent any moisture tracking across the cavity without the use of a DPC. They are light to handle, robust and easily cut without the use of specialist tools or equipment. Large grooves give improved adhesion for mortar and an accurate guide when cutting to the required width. Another unique feature is how two pieces can be easily joined together, eliminating waste.

Multi-Cav Cavity Closures are the ideal 1st and 2nd fix solution for use with timber, metal, PVC windows and door frames. They eliminate time and the costly process of cutting bricks and blocks to close the reveal.

Solving the Problem of Thermal Bridging:

Multi-Cav Cavity Closures avoid thermal bridging occurring at window and door openings preventing heat loss and condensation by complying with the Accredited Construction Details. These recommend a minimum thermal resistance path through a proprietary cavity closer of 0.45m2 K/W as calculated using the BRE method. Multi-Cav Cavity Closures with a minimum overlap of 30mm by the window frame over the cavity closer have a resistance value of 0.67m2 K/W.


When installing Multi-Cav Cavity Closures the vertical jamb lengths should be cut to the required size and installed first. An additional 80mm should be allowed to ensure an overlap of the sill by 50mm.This is achieved by cutting away the UPVC flange or by sliding the flange through the foam and trimming at the top. The horizontal sill length is then cut to the required size and installed. More information about installation can be downloaded here