The Box Sash Workshop

In our experience the poor maintenance of box frames and sashes is the number one reason for the need for restoration, this can be due to paint work being allowed to crack and open up allowing water ingress, causing first wet rot, and if not dealt with at this stage, dry rot which is the ultimate killer of windows. or beetle infestation, which can be treated if caught early enough.

In order to restore a box sash window in situ, we would remove the staff beads, take out the sashes and cut the cords. We would them open up the pockets to retrieve the weights and at this stage assess the sashes, sill, inner and outer liners and also the pocket liner.

This process will allow us to judge the extent of the remedial work needed. We would strip the sashes and box frame of all paint, being careful to preserve the original glass which will be very thin and brittle in most cases. If the sashes have no sign of rot or beetle infestation, we would treat them with preservative, rot and beetle, then place them to one side. If there was signs of rot we would remove the infected area well into good wood, we would then shape reclaimed pitch pine and cut in using a water proof wood glue, then screw using brass screws if required.

We would then move onto the box frame. Wet rot is what we would normally expect to find, especially to the top and underside of the sill. The outer liner and pocket liner would normally suffer from varying degrees of rot, normally at the junction with the sill. If this is the case we remove the sill from the frame, cut out the infected areas back to good wood, and again cut in reclaimed pitch pine replacements, and then glue and screw using brass screws, this would also apply to the liners, once everything is cleaned up and sanded back to a perfect fit, we would treat the box frame, allow it to dry and then redecorate using oil based primer, undercoats, and usually gloss oil based top coats. At this stage we would normally recommend a micro porous paint system. The client would have the choice of draught exclusion systems.

Once the window is re weighted and rebuilt the client can look forward to many years of pleasure, because surely there is nothing more aesthetically pleasing than a traditional box sash window in all its glory!