Preserving historic window frames
Renovate the windows you have instead of replacing them: rot repaired, joints strengthened, cords and weights renewed, re-puttied and painted — with vacuum glazing and seals fitted while the sashes are out.
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Sash window renovation
Renovate your windows instead of replacing them
We renovate old box sash windows. With the materials now available — vacuum glass, modern sealants, grooved seals, timber repair systems — restoration is a cost-effective alternative to full replacement. It saves time, money and the look of a historic window.
Double glazing and draught-proofing together eliminate draughts and improve thermal efficiency and comfort. The same work also reduces noise and heating bills.
What are the main advantages of sash window preservation?
Two things done together — restoring the wooden frames and reglazing the sashes — give an aesthetic and economical renovation of wooden windows:
- Suitable for Grade II listed properties: the windows look identical, with no loss of glass area, subject to consent.
- Economical, because the intervention is fast and needs relatively little new material.
- Timber is repaired with timber; the character of the joinery is kept.
- A renovated and insulated window — not only thanks to the glass, but above all thanks to the seals placed in grooves (the professional method) in the sashes and the frame.
- Energy savings and comfort from the first night after the work.
What restoration covers
Timber repairs
Rot is cut back to sound wood and replaced with new timber spliced and glued into the original — bottom rails, sill noses, the feet of the pulley stiles. Loose mortice-and-tenon joints in the sashes are re-glued and pinned. Where a sash is beyond repair, a new one is made to match the original sections and glazing-bar profiles.
Cords, weights and pulleys
Cords are renewed on every window that is reglazed, the weights are adjusted for the heavier glass, and worn pulleys are replaced. A sash should sit where you leave it and move with one hand; if it does not, the balance is wrong.
Putty, paint and furniture
Old putty is removed with the glass. After reglazing, the exterior is re-puttied to the original line, primed and painted; the interior is made good where the work has disturbed it. Original brass and iron furniture is cleaned and refitted; missing pieces are replaced with traditional patterns.
Draught-proofing
With the sashes out, grooves are cut for wiper seals in the sliding surfaces and compression seals where the meeting rail and bottom rail close. This is the part that stops cold air moving, which no amount of glazing does on its own. Draught-proofing explains the seals and what they can and cannot do.
Sash window preservation examples
Georgian, Victorian and Edwardian sashes on the same street can need very different work: one has a rotten sill, the next has been painted shut for thirty years, the third has had its glazing bars removed by a previous owner. The survey looks at each window on its own and the quote is itemised the same way, so you can see what restoration, glazing and seals cost per window.
The projects gallery shows finished windows; how it works shows what happens in between.
PROJECTS GALLERYFAQ
My windows are very rotten — can they be repaired?
Wooden windows that have not been maintained for years can look so far gone that replacement seems the only option. In most cases that is appearance: faded and cracked paint, badly degraded putty around the panes and some rot in the lower parts of the window — the bottom rail of the lower sash, the sill, the foot of the box. Underneath, most of the frame is usually still solid and has kept its strength.
Damaged parts are cut out and replaced with new timber, both on the sashes and on the box frame where the pulleys and cords are hidden. The exterior is then re-puttied, primed and painted.
Will my sashes take the additional weight of double glazing?
Yes. A vacuum unit is roughly twice the weight of the single 4 mm pane it replaces, and even old sashes can carry it and still slide properly. During the reglazing the joints are repaired and strengthened, and around 30% more weight is added to the counterbalance in the box so the sash stays where you leave it.
How do I clean and treat old metal window furniture?
- Unscrew the metal parts: fastener, lock keep, security hook, sash lift, arm stay.
- Brush them with a wire brush.
- Treat the rust with rust remover, or paint remover if they are painted over.
- Let the pieces dry in the open air after any liquid treatment.
- Repaint with an anti-rust paint — or, if the furniture is brass, simply polish it.
How do I fill an old screw hole in a wooden window?
- Remove the screw that is turning in the hole.
- Enlarge the hole with a drill.
- Glue a wooden dowel into the hole.
- Let the glue dry.
- Cut the dowel flush with a flush-cut saw and re-drive the screw.
Do you replace sash cords and pulleys?
Yes, as part of any reglazing — the sashes are out, the pockets are open and the weights are being changed anyway, so new cords go in as a matter of course. If one cord on a window has failed the others are usually close behind, so all four are renewed together. Worn pulleys are replaced with like-for-like cast pulleys.
Sash window double glazing works in partnership with
Vacuum insulated glazing supplied made to measure for each sash by manufacturers including FINEO (AGC Glass Europe, Belgium).
Request a quote
Send us the number of windows, their style and your postcode and we will come back to you with the next step — usually a survey visit.