Sash Window Restoration: What It Involves and What It Costs

Sash window restoration brings old timber windows back to full working order: rotten wood is repaired, the sashes slide smoothly again, draughts are sealed and the paintwork is renewed. A full restoration typically costs £600 to £1,200 per window, a fraction of the price of a new timber sash, and it keeps the original character of your home. This guide explains what is involved, what it costs and how to tell whether your windows can be saved.

Restoration, overhaul or replacement?

These terms are often used loosely, so it helps to know what you are being quoted for.

Job	What it usually includes	Typical cost per window
Basic repair	One fix, such as a broken cord or a sticking sash	£70 to £300
Overhaul	New cords, freeing and balancing the sashes, draught-proofing	£350 to £650 (London £450 to £750)
Full restoration	Overhaul plus timber repairs, re-glazing and redecoration	£600 to £1,200
Replacement	A new timber sash window, made and fitted	£1,200 to £3,500

Prices are typical UK ranges for 2026 and include VAT. London and the South East are usually 20 to 30% higher.

What a full restoration involves

1. Survey: the specialist checks every sash, frame and sill for rot, movement and damage, and agrees what will be repaired.
2. Removing the sashes: the beads are taken off and the sashes lifted out, usually one window at a time so the room is never left open for long.
3. Timber repairs: soft or rotten wood is cut out and new timber spliced in, or small areas are repaired with resin. Sills and bottom rails are the most common problem areas.
4. Re-cording and balancing: new sash cords are fitted and the weights adjusted so each sash stays where you leave it. See our guide to repairing a sash window cord.
5. Re-glazing: cracked panes are replaced and loose putty renewed. Original glass is kept where possible.
6. Draught-proofing: brush seals are routed into the beads and meeting rails. Read more on stopping draughts from sash windows.
7. Redecoration: the windows are prepared, primed and painted.

Most restorations are done on site, a window at a time. A typical house takes a few days to a couple of weeks, depending on the number of windows and how much timber repair is needed.

Can your windows be saved?

Most sash windows that look tired can be restored. Signs they are good candidates:

• The timber feels solid when pressed with a screwdriver, apart from small areas.
• The frames are square and the sashes are the right size for the box.
• Problems are rattles, draughts, broken cords or flaking paint.

Signs replacement may be better:

• Rot runs through large parts of the frame, sill and sashes.
• The window has been badly altered or is distorted.
• You want a different style or glazing that the existing sashes cannot take.

If you are unsure, read sash window repair or replacement: which is right for you? and ask a specialist to survey the windows before you decide.

Why restoration is often the better choice

• Cost: restoring a window usually costs a third to a half of replacing it.
• Character: original timber, glass and mouldings are what give period homes their value.
• Planning: restoration rarely needs permission, even in a conservation area or on a listed building, where replacement often does.
• Longevity: a well-restored timber sash window can last for decades more with regular painting.

Can restored windows be made warmer?

Yes. Draught-proofing alone makes a noticeable difference. For more, you can add secondary glazing inside, or in some cases fit slim double glazing or vacuum glass into the existing sashes. See can you double glaze existing sash windows?

What affects the price

• The number of windows (whole-house jobs are usually cheaper per window)
• How much rot needs repairing
• Window size and glazing pattern
• Access, such as scaffolding for upper floors
• Location, with London prices highest

For individual repair prices, see our sash window repair costs price list, and for the full picture of new windows, our sash window replacement cost guide.

Questions to ask a restoration specialist

• Do you splice in new timber or only use filler?
• Which timber do you use for repairs?
• Is draught-proofing included, and which system do you use?
• Do you work on one window at a time, and do you leave the house secure each night?
• What guarantee do you give on the work and the paint finish?

Find sash window restoration specialists near you and compare quotes.

Frequently asked questions

How much does sash window restoration cost?

A full restoration typically costs £600 to £1,200 per window in the UK, depending on the amount of timber repair. London prices are usually higher. A simpler overhaul costs £350 to £650.

How long does sash window restoration last?

A properly restored timber sash window can last for decades, provided it is repainted regularly, typically every 3 to 5 years for softwood.

Is it worth restoring old sash windows?

Usually, yes. Restoration costs far less than replacement, keeps the character of the house and rarely needs planning permission.

Can rotten sash windows be restored?

Most can. Rotten sections are cut out and replaced with new timber. Only windows with widespread rot through the frame and sashes normally need replacing.

Sources

Prices from Best Builders sash window cost guide (updated September 2026) and MyBuilder sash window repair cost guide (updated August 2026).