Historic vertical sliding sash window renovation guide

This article was published on December 13, 2016

Making Windows Beautiful again:

By their very nature, many traditional sliding sash windows are over 100 years old and with some dating back to the 1800s, it’s not surprising that draughts, rattles and operational issues are all too common.  We recently organised a Conservation and Heritage Workshop for local conservation officers from across the North East. During the seminar delegates were able to see first-hand the techniques that our skilled team uses to renovate and refurbish timber windows. There was in particular interest in just how bad a state of repair a window could be in for us still to be able to renovate it. So we thought we’d share the technique in this blog.

ERW’s Full Draught Sealing system – for windows where both sashes slide. Installation is similar for the half draught sealing system except only the bottom sash slides and the top sash is sealed.

1. We carefully release the sashes and remove them from their aperture and they’re planed and adjusted to align well
2. Where fitted, sash cords are renewed, balance weights added as necessary and pulleys serviced. Where the sashes are counter-balanced using springs, we service / re-tension them if required
3. Barrel locks fitted through the meeting rails will usually be removed and the holes filled as they can often interfere with weather stripping. We then recommend the locking catches to be fitted at the meeting rails depending on the size of the window
4. The ERW Draught Sealing System is then installed in the meeting rail and the new staff beads with draught seals pre-installed are provided around the inside of the frame
5. The parting bead (between the two sliding sashes) is replaced with a new timber parting bead that also incorporates a draught seal
6. Thanks to our innovative Easy Paint System (suitable for sliding sash windows with sash cords only) the staff beads are fitting using press-studs / screws that allow for easy future removal when required for painting or repairs, without the need for scaffolding. The sides of the top and bottom sashes are fitted with concealed housings to accept the demountable sash cords fitted. When the staff beads are removed, the bottom sash simply lifts out and the sash cord is disengaged

Permanent Seal – for when sashes are sealed and non-operational

1. If the sashes have sufficient gaps to take a bead of sealant with level meeting rails but aren’t required to be operational, we seal in the sashes and pulleys and screw together the meeting rails with countersunk screws from security.
2. If the sashes are painted shut with meeting levels not level, we release and remove the sashes, then plane and adjust them for perfect alignment. Sashes and original staff and parting beads are then refitted and the sashes sealed.

Timber Repairs

1. During installation of the ERW draught sealing system, any defects in the sashes and frames are made good and primed for painting
2. Repairs are carried out where appropriate with the ER 2 Part epoxy repair system which is a durable, strong resin material that will not crack or rot, making it perfect for the repair of joints
3. During the process, decayed or damaged timber is routed out to expose prime wood which then sealed and stabilised using a special stabilising solution. Cavities formed after routing are filled with bulk filler and finished with the 2-part epoxy resin before being moulded to match the existing profile and sanded
4. Partial or full replacement of timber may be appropriate for some repairs such as linings, outer cheeks or glazing bars.

STEP ONE any decaying timber is routed out to expose the ‘sound’ timber

STEP TWO The exposed timber is then treated

STEP THREE Timbabuild epoxy resin is used to fill the cavities in the timber

STEP FOUR The epoxy resin is moulded to match the existing profile of the timber

STEP FIVE  The window frame is then painted