FlushSash Hints & Tips

Due to the design and slimness of the FlushSash profile, there are elements that are critical to the windows performance and finished aesthetics. We thought it may be useful to flag these elements up for consideration by the respective members of your team.


Glazing packer placement and sizes are critical to sash operation as well as giving consistency to the shadow line dimensions between sash and frame both internally and externally. We know that you have been installing windows for years but we thought it might be useful to attach the guidelines for packer placements.

A= Bridge packer. Use on lower horizontal rails, min 2 per rail. Position not to interfere with drain slots. Additional packers are required for lengths greater than 1500mm.

B= Glazing packers. Use to pack the glass unit into the apertures.

C= Additional glazing packers. Position adjacent to locking points or cavity locking wedges in sashes and frames, and to space the glass on longer rails.


The sculptured bead for 28mm glazing is a small profile with a ‘busy’ shape makes the importance of cutting it the optimal length and placing the beads in the correct position extremely important to give acceptable bead joints. Sash UK will ensure the bead is cut correctly and placed in the correct position. When glazing on site, it’s more important than on any other sashes to return beads to the same position as removed from.

Fixed Panes

Because this new sash is an addition to the FS suite, the beads used in the sash differ ever so slightly from those used in fixed panes (see image below). If this is seen as an issue, there is an option to use dummy sashes in lue of direct glazed fixed panes. The timber equivalent of FLushSash typically uses dummy sashes due to the way such products are manufactured.

Image 2


The exposed weatherseal flipper on the sash edge externally is designed to optimise the weather performance of the system across, air, wind and water. The weatherseal does an excellent job having gained top rating of class 4 across air, wind and water in testing. The design of the flipper system sees it sealing against an insert in the bead channel of the outerframe. However, the flipper has to switch from concave to convex when the sash opens and as such results in the need to push the sash open initially to force the flipper over. This is a feature of the system to ensure there is no compromise in the weather performance.#