Sash Window Repair Cost Calculator

Select which repairs your sash windows need and get an instant cost estimate based on 2026 contractor rates.

This calculator uses average UK contractor rates from Checkatrade and MyBuilder quotes (January 2026). Actual costs vary by region (London +15-25%, Scotland/Wales/North -10-15%), property access (scaffolding adds £400-£800 for a whole house), and timber condition.

Calculator

How many sash windows need repair?

Select repairs needed:

Replace sash cords (£120-£180 per window)
Broken cords, sash won't stay open. Includes both sashes, weights adjusted.Replace broken glass (£80-£250 per window)
Cracked or broken panes. Price for single glazing, standard sizes. Georgian bars add £40-£70.Fit draught seals (£140-£280 per window)
Brush or compression seals in staff bead and parting bead. Reduces heat loss by 25-40%.Strip and repaint (£200-£400 per window)
Remove old paint, sand, prime, undercoat, 2 gloss coats. Includes both sashes and frame.Repair rotten sill (£150-£350 per window)
Splice in new timber, epoxy filler for minor rot. Full sill replacement adds £100-£200.Replace locks and fasteners (£40-£80 per window)
New sash fastener, cill lock, or sash stops. Traditional Brighton pattern or modern cam lock.Replace pulleys (£60-£120 per window)
Worn or seized pulleys. Price for brass axle pulleys, pair per window.

What's Included in Each Repair

Sash Cord Replacement (£120-£180)

Replace all 4 cords (2 per sash), adjust sash weights to balance the new cord length, test operation. Takes 2-3 hours per window. DIY cost: £15-£25 in materials (cotton sash cord £8/10m, time).

Glass Replacement (£80-£250)

Remove broken glass, measure and cut new pane, fit with putty and glazing sprigs. Price varies by glass area and type. Float glass £80-£140 per window, crown glass (period authentic) £180-£250. Georgian bar windows add £40-£70 for the extra small panes.

Draught Sealing (£140-£280)

Fit brush pile or compression seals in staff bead (inner frame) and parting bead (between sashes). Adjust sashes for smooth operation. Professional installation £140-£280, DIY kits £30-£60 per window (Reddiseals, Mighton). Saves £60-£120 per year in heating per window.

Strip and Repaint (£200-£400)

Remove old paint with heat gun or chemical stripper, sand smooth, fill defects, prime bare timber, apply undercoat and 2 gloss coats. Takes 1-2 days per window including drying time. DIY cost: £40-£80 in materials, 8-12 hours labour.

Sill Repair (£150-£350)

Cut out rotten timber, splice in new hardwood section, epoxy fill small voids, sand and paint to match. Minor repairs (under 30% of sill) £150-£220, major repairs or full sill replacement £250-£400. Uses hardwood (iroko, sapele, oak) to match durability of original.

When to Repair vs Replace

Repair your sash windows if:

Timber rot affects less than 30% of the frame (repairable with splicing)
The sashes operate smoothly and are square in the frame
You're in a conservation area or listed building (like-for-like repair required)
Total repair cost is under 60% of replacement cost (£600-£800 repairs vs £1,200+ replacement)

Replace your sash windows if:

Timber rot exceeds 30% (multiple sill, rail, and stile repairs needed)
The box frame is rotten (very expensive to repair, £800-£1,500 per window)
You want double glazing (slim DG retrofit £800-£1,600 or full DG replacement £900-£2,200)
Total repairs exceed £800-£1,000 per window (cheaper to replace with new timber at £900-£1,400)

See our refurbishment cost guide for the full repair vs replace decision framework.

Sources

Repair rates verified against:

Checkatrade sash window repair quotes (Jan 2026, 12 contractors, London/Southeast)
MyBuilder itemised repair quotes (Dec 2025-Jan 2026)
Ventrolla, Sash Window Workshop trade price lists (contractor rates, Jan 2026)
DIY material costs from Mighton Products, Reddiseals, Travis Perkins

Related Guides

Sash Window Repair Costs Breakdown — detailed repair pricing
Sash Window Refurbishment Cost — repair vs replace decision
Draught Proofing Cost Guide — energy saving costs