Structural Cavity Closers by Subframes

Subframes UK is the nation’s largest supplier and manufacturer of structural cavity closers for windows and doors.

A structural cavity closer gives a secure fixing surface at the reveal, so a door or window frame fixes straight into the closer with strong screw retention. That direct fixing removes the reliance on brackets, straps or masonry fixings and the movement they can allow, for a stable installation on heavier openings. Traditional methods only give a fixing where a solid surface happens to fall, whereas the closer takes a fixing at any point along its full length.

We manufacture every closer at our Midlands factory and each one is subject to rigorous quality control before it leaves the facility.

For quotations, product information or technical support, contact us on 01773 590100 or email [email protected]

A secure fixing surface for doors and windows

On a standard opening, a fitter often has no solid surface to fix into, so the frame is tied back into the blockwork with straps or long masonry screws that can shift over time. A structural cavity closer removes that reliance by taking the frame fixings directly into its reinforced core, which holds the frame square and steady for the life of the door or window while allowing it to be removed and refitted if required.

This is most relevant on heavier or more exposed frames. Entrance doors, French doors, patio doors and bifold doors all sit more securely with a direct fixing. This high quality direct fixing detail greatly removes the chance of frame movement over time and thus the need for remedial adjustments at a later date.

Sizes and configurations

We supply structural cavity closers in 100mm, 125mm and 150mm profiles, either as structural door packs or made up into a pre-formed cavity closer in two-, three- or four-sided configurations. Every structural closer includes 20 brick ties so it can be secured into both the brickwork and blockwork.

For standard openings that do not need a structural fixing, our cavity closers range from 50mm to 300mm in cavity widths.