Cavalok Frame Former

Cavalok is a PVC-u multi-purpose frame former, window frame receptor and cavity closer acceptor that provides accurate openings for masonry cavity walls enabling quick and easy installation of windows and doors.

A specially designed moulded corner block enables simple self assembly of a frame former and window receptor. There is no need for mitre cuts, welding, specialist tools, specialist skills or separate installation of Timber Frame Formers, Cavity Closures or DPC.

Available in 6 metre lengths to fit cavity widths of 50 – 150 mm Cavalok is suitable for use with any manufacturers timber, metal or PVC-u windows and doors.

Cavalok is also available in pre-assembled units and in kit form. These come complete with timber bracing and wall ties.

Solving the Problem of Thermal Bridging:

Cavalok avoids thermal bridging occurring at window and door openings preventing heat loss and condensation. Complying with current Building Regulations (2002) Part L1 and L2 for Conservation of Fuel and Power.


The coursework should be built to the level of the sill ensuring that it is flat, level and free from excess mortar. Locate the closure in the required position, ensuring that it is facing the correct way and prop vertically. Build up the outer coursework by a single level on one side and butt up the frame. Confirm that the frame is correctly positioned horizontally and held firm vertically, then check for accuracy in both planes, ensuring that there is no twisting. Use a tape measure and spirit level to confirm this.

More information about installation can be downloaded here