Sash Window Refurbishment Cost
What full sash window refurbishment costs, when refurbishment makes more sense than replacement, and how to decide between repair and new windows.
Sash window refurbishment costs £600-£1,200 per window for full restoration including timber repair, re-glazing or slim double glazing retrofit, draught proofing, re-cording, and repainting. Basic refurbishment (re-cord, clean, repaint, draught seals) costs £350-£600. Full structural refurbishment (splice in new timber, retrofit slim DG, full strip and repaint) costs £900-£1,500. Refurbishment makes sense if timber rot is under 30%, the property is listed, or windows are pre-1900 originals. Replacement costs £900-£2,200 per window but is better for frames with over 40% rot.
Last reviewed: 2026-07-20 • 5 min read • Verified against 6 restoration specialist quotes
Sash Window Refurbishment Cost Breakdown
Refurbishment costs vary by scope of work. Most specialists quote per window based on condition after survey. Prices below are for standard Victorian or Georgian timber sash windows (January 2026).
| Refurbishment Level | Work Included | Cost per Window |
|---|---|---|
| Basic service | Re-cord, ease sticking, draught seals, repaint | £350-£600 |
| Standard refurb | As above + minor timber repair, re-glaze if needed | £600-£900 |
| Full refurbishment | As above + sill splice, slim DG retrofit, full strip/repaint | £900-£1,500 |
| Structural rebuild | Replace 30-50% timber, rebuild sashes, slim DG, repaint | £1,200-£1,900 |
Most period property sash windows need standard to full refurbishment. Basic service works for well-maintained windows needing re-cording after 20-25 years. Structural rebuild applies when frames are badly deteriorated but you want to save the original boxes (listed buildings, conservation areas).
What Full Sash Window Refurbishment Includes
A typical full refurbishment (£900-£1,500 per window) involves removing the sashes, repairing timber, upgrading glazing, and reinstalling with draught proofing. Here's the detailed breakdown.
1. Survey and Removal (£80-£140 per window)
Specialist surveys the windows, measures rot extent, checks box frame condition. Sashes are removed via the staff beads and parting beads. Box pockets are opened to access weights. Old cords cut and weights removed.
2. Timber Repair (£150-£500 per window)
Rotten timber is cut out and replaced with new timber spliced in (scarf joint or dutchman repair). Common repairs:
- Sill splice: £200-£400. Bottom 100-200mm of sill cut out, new timber scarfed in with waterproof epoxy and stainless screws.
- Meeting rail repair: £120-£220. Rotten sections of the horizontal meeting rail replaced.
- Stile bottom repair: £150-£280. Lower sections of vertical stiles (often rot where they meet the sill) cut and spliced.
- Parting bead replacement: £40-£80. Worn or broken parting beads (separates upper and lower sash) replaced with new timber.
Timber repair accounts for most variation in refurbishment cost. Windows with minimal rot (10-20%) cost £150-£250 in timber work. Windows with 30-40% rot cost £400-£600.
3. Re-Glazing or Slim DG Retrofit (£180-£600 per window)
Two options for glass:
- Re-glaze with single pane: £180-£280. Old glass and putty removed, new glass cut and puttied in. Maintains original appearance for listed buildings requiring single glazing.
- Retrofit slim double glazing: £400-£600. Sashes routed deeper (18-22mm rebate), 14-18mm slim DG units fitted. Achieves U-value 1.8-2.2 W/m²K vs 5.0+ for single glazing.
Slim DG retrofit adds £220-£320 per window versus single glazing but saves £40-£60 per year in heating costs (typical Victorian window, 1.2m²). Payback period: 4-6 years.
4. Re-Cording and Balancing (£100-£160 per window)
New sash cords fitted (waxed cotton or modern synthetic), weights adjusted for the new glass weight (heavier for DG), pulleys lubricated or replaced if worn. Sashes rehung and balanced so they stay open at any position.
5. Draught Proofing (£140-£280 per window)
Brush seals or compression seals fitted to staff beads, parting beads, and meeting rails. Reduces draughts by 80-90% and improves thermal performance. See our draught proofing cost guide for details.
6. Repainting (£200-£380 per window)
Sashes stripped (chemical stripper or heat gun), primed, undercoated, and top-coated with exterior wood paint. Includes cutting in glass edges and painting internal faces. Listed buildings sometimes require linseed oil paint (add £150-£250 per window).
Refurbishment vs Replacement: Cost Comparison
| Scenario | Refurbishment Cost | Replacement Cost (Timber) | Better Choice |
|---|---|---|---|
| Less than 20% rot, sashes sound | £600-£900 | £1,050-£1,400 | Refurbish (saves £450-£500) |
| 20-30% rot, box frame good | £800-£1,200 | £1,050-£1,400 | Refurbish (marginal saving, keeps original fabric) |
| 30-40% rot, structural concerns | £1,100-£1,700 | £1,050-£1,400 | Replace (unless listed building) |
| Over 40% rot, box frame failing | £1,400-£2,200 | £1,050-£1,400 | Replace |
The crossover point is around 30-35% timber rot. Below that, refurbishment saves money and preserves the original windows. Above that, replacement makes more financial sense unless the property is listed.
When Refurbishment Is the Right Choice
Choose refurbishment over replacement if any of these apply:
- Listed building: Listed building consent usually requires retaining and repairing original fabric where possible. Refurbishment is the default, replacement needs strong justification (structural failure).
- Conservation area: Many conservation areas prefer retention of original windows. Refurbishment avoids planning permission (repair is permitted development). Replacement may need permission.
- Pre-1900 windows with heritage value: Original Georgian, Victorian, or Edwardian sashes have historical significance. Refurbishment preserves this.
- Rot under 30%: Economically viable to repair rather than replace.
- Long-term ownership (40+ years): Refurbished timber windows can last another 60-80 years. Replacement UPVC needs replacing after 25-35 years.
- Environmental concerns: Refurbishment saves 80% of embodied carbon vs new timber manufacture and disposal of old windows.
When Replacement Is Better
- Timber rot exceeds 40% of frame volume (uneconomic to repair)
- Box frames are structurally unsound (collapsing sills, rotten pulley stiles)
- Sashes are severely warped or twisted (can't be planed true)
- Refurbishment quote exceeds 80% of replacement cost
- Property is not listed and you want low-maintenance UPVC
For full replacement pricing, see our sash window replacement cost guide.
Full House Refurbishment Costs
| Property Type | Window Count | Standard Refurb (£600-£900) | Full Refurb (£900-£1,500) |
|---|---|---|---|
| Terraced 2-bed | 8-10 windows | £4,800-£9,000 | £7,200-£15,000 |
| Semi-detached | 12-14 windows | £7,200-£12,600 | £10,800-£21,000 |
| Detached 4-bed | 18-22 windows | £10,800-£19,800 | £16,200-£33,000 |
Most refurbishment specialists offer discounts for whole-house work (5-15% off per-window rates when doing 8+ windows in one project).
Sources
Pricing verified against:
- Ventrolla sash window refurbishment quotes (London, Southeast, Midlands, 2025-2026)
- The Sash Window Workshop restoration price list (Jan 2026)
- Bygone Windows refurbishment vs replacement quotes (Dec 2025)
- Historic England advice on timber window repair in listed buildings (Oct 2025)
- MyBuilder restoration specialist quotes (regional pricing, 2025-2026)
Related Guides
- Sash Window Replacement Cost — full replacement pricing
- Sash Window Repair Costs — individual repair pricing
- Box Sash Window Restoration Cost — full box restoration
- Double Glazed Sash Windows Cost — slim DG retrofit