How a sash window works, and what goes wrong
A box sash window has two sliding frames, called sashes, that run up and down in a hollow timber box. Inside the box on each side hang heavy weights, tied to the sashes with cords that run over pulleys at the top. When everything is balanced, a sash stays where you leave it and moves with one hand.
Over the years the cords fray and snap, and the sash either crashes down or will not stay up. Layers of paint glue the sashes to the beads (the thin strips of wood that hold them in their tracks). Pulleys seize. Gaps open up so the window rattles every time a bus goes past. None of these faults mean the window is finished. They are all normal wear on a part that was always meant to be maintained.
Sash window repair in Fulham terraces and flats
Plenty of Fulham's Victorian and Edwardian terraces, and the flats many of them have since been split into, still have their original sashes. Large bay windows on the ground floor, narrower sashes upstairs and small sashes on the back additions are all common. Each one is taken apart in the same way, which is what makes sash window repair in Fulham such a regular job.
We remove the staff beads on the inside, lift out the lower sash, take out the parting beads, then the upper sash. Through the pocket (a small removable panel low down in the box) we reach the weights. New cord is fitted to each side, the pulleys are freed and waxed, and the sashes go back in and are tested until they glide.
Jobs we cover
- Replacing broken or frayed sash cords
- Freeing and waxing seized pulleys
- Freeing sashes that are painted shut
- Fitting new staff beads and parting beads
- Easing sticking and binding sashes
- Splice repairs to rotten sills and bottom rails
- Reglazing cracked panes with putty
- Fitting sash stops and catches
- Rebalancing sashes that will not stay up
Sticking, rattling and painted shut sashes
A window that has been painted shut can usually be freed by cutting through the paint line carefully on both faces. Old paint on Fulham windows is often many coats deep. The Health and Safety Executive says lead paint was widely used in homes until the 1960s, so we avoid dry sanding or burning old paint and only strip back what is flaking.
Rattling is usually down to worn beads or a sash that has shrunk. Moving the staff bead closer, or fitting a new parting bead, takes up much of the slack. If you also want the gaps sealed against cold air, our draught proofing service fits brush strips into the beads and sashes as part of the same job.
Rotten sills, broken glass and small timber repairs
Sills and the bottom rail of the lower sash take the worst of the rain. Where rot is limited to one area, the soft timber is cut out and a new piece of matching wood is glued and shaped in, which is called a splice repair. Smaller patches can be filled with a resin filler made for exterior timber.
Cracked panes can be reglazed using putty, and a missing horn (the little decorative stub at the bottom corners of the upper sash) can be shaped to match the others. If most of the frame has gone soft, we will tell you honestly that it needs a joiner or a replacement window rather than patching it.
Repair or replace: building regulations and planning
Repairs are the straightforward route. The Planning Portal says building regulations do not normally apply to work such as replacing broken glass, rotten sashes or parts of the frame. Replacing the whole window, frame and all, is different. That is covered by building regulations and must either be approved by building control or fitted by an installer registered with a competent person scheme such as FENSA or CERTASS, who can certify their own work.
Planning is a separate question. Hammersmith and Fulham Council says replacement windows on a single house do not generally need planning permission unless the frame material changes, for example timber to PVCu, but permission may be needed if the house is covered by an Article 4 direction. In flats, replacements must match the originals in look and material to avoid needing permission, and listed buildings need consent for replacement windows. About half the borough sits in conservation areas, such as Central Fulham and Walham Grove, so ask the council before swapping timber sashes for anything else.
Where we work
We cover all of SW6, and regularly repair sashes in Parsons Green, Fulham Broadway and across the river in Putney. If you have several windows that need attention, list them on your quote request with a photo of each. It helps us plan how many cords and beads to bring.
Who this suits
- Owners of Victorian and Edwardian terraces with original sashes
- Flat owners in converted houses with large bay windows
- Landlords with sash windows that tenants cannot open
- Homes in conservation areas where keeping timber windows matters
- Anyone told their sashes need replacing who wants a second opinion
Common questions
Do you replace both cords when one has snapped?
We usually recommend it. If one cord on a sash has gone, the other is the same age and often close to breaking. Doing both sides at once saves taking the window apart twice.
Do I need building regulations approval to repair sash windows?
Not normally. The Planning Portal says work such as replacing broken glass, rotten sashes or parts of the frame does not normally fall under building regulations. Replacing the whole window, frame and all, does.
Can I swap my sash windows for uPVC in Fulham?
Hammersmith and Fulham Council says a change of frame material usually needs planning permission on a house, and flats need like for like replacements to avoid it. Article 4 directions and listed status can add more controls. Check with the council first.
My upper sash has slipped down. Can it be fixed?
Yes. It usually means the cords on the top sash have broken. Getting to the top sash means removing the lower one and the parting beads first, so it takes a little longer than a lower sash.
Will you need to take the window out of the house?
No. The box frame stays in the wall. Only the sashes and beads come out, and each window is put back together and working before we leave.
Can you fix a sash with a cracked pane?
Yes. The old putty and glass are removed, a new pane is cut to size, and it is bedded and finished in fresh putty. The putty needs time to firm up before it is painted.
Is it worth repairing old sash windows?
In most cases, yes. Good quality old timber lasts well when it is painted and kept up, and most faults are in the cords, beads and paint rather than the frame itself.