Single and Double Flange

Classic 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. Classic Closures provide a simple low cost, effective 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. A unique feature is how two pieces can be easily joined together, eliminating waste and large grooves give improved adhesion for mortar.

Classic Closures are available in widths from 50mm to 300mm and 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:

Classic 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 0.45m²K/W as calculated using the BRE method.

Classic Closures with a minimum overlap of 30mm by the window frame over the cavity closer have a resistance value of 0.67m² K/W.


Classic Closures, being so versatile, can be fixed to the window frame, installed during wall construction or retro-fitted after the wall construction is complete.

More information about installation can be downloaded here