As required under BS 8213 – 4: 2016 (9.8.5) frame packers should be used adjacent to fenestration fixing positions to;

a) Prevent outer frame distortion during installation and use.
b) Ensure that the frame remains centralised, level and square
c) Allow for thermal movement of the frame
d) Assist in withstanding wind loadings

These packers should normally be left in situ and concealed as part of the completed installation. In this case the fixings should be tightened so that the frame is held securely against them.

Dynamic forces from use with doors mean that additional packers should be used adjacent to the hinge and locking points. Glazpart’ s frame packers are resistant to rot, and corrosion and overtightening of fixings should be avoided as this leads to distortion and should be avoided.

Indeed, Secured by Design (SBD) recommend the installation of frame packers

“46.12 Due to the dynamic forces experienced when windows are opened and closed, frame packers should be used. This will limited outer frame distortion during installation and use, ensure that the frame remains centralised, level and square and allow for thermal movement in the frame.” – Residential (Homes) Guide 2025 Edition 1

These packers are designed for use during the installation of the window frame into the window reveal. Their function is to prevent the deflection of the frame during the installation, increase security around the fixing point and support the frame so it can be installed plumb (vertical). The “U” shaped design allows for a packer to be installed around the fixing and supporting the fixing point.

Once installed correctly with the fixings the frame is then square so that the insulated glazed unit can be installed.

These packers are designed for use during the installation of the window frame into the window reveal, exactly as with a spring frame packer. However, the design incorporates a “klip” function and installation “tab”.

This klip exerts a lateral force between the frame packer and the fixing, holding it in place preventing any rotation of the frame packer and it falling out.

The additional tab makes the location of the frame packer even easier, especially when working at height and once the window is in position the tab is bent over, breaking off.

The advantages of this design are that once in position it can be released by the installer, freeing up a hand to install the fixing correctly, easily and safely (especially when working at height).

These packers are designed for use during the installation of the window frame into the window reveal, exactly as with a standard frame packer. However, the design incorporates a “spring” function. This spring exerts a lateral force between the reveal and the window frame supporting it in the gap.

The advantages of this design are that once in position it can be released by the installer, freeing up a hand to install the fixing correctly, easily and safely (especially when working at height). In addition this prevents the frame packer rotating and falling out. This would then have to be reset or if the frame packer falls into the cavity, replaced.