Sash window restoration in the UK: compare timber repairs and working parts

Compare Chameleon and The Sash Window Man against the same window-by-window repair schedule, separating timber work, working parts, draught-proofing and finishing rather than choosing on headline price.

Chameleon describes its coverage as East Anglia, London and the Home Counties, and says it works in many but not all parts of London.[1] The Sash Window Man lists London and Brighton contacts and advertises services around Wimbledon and Wandsworth.[2][3] Check postcode availability with both.

The Sash Window Man’s refurbishment factsheet is a PDF uploaded in 2015; confirm its terms still apply before relying on them for a quotation.[2]

Chameleon vs The Sash Window Man

The main distinction is between the proposed timber intervention and the operating overhaul. Chameleon sells one package in three levels, from draught-proofing only to full restoration with slim double glazing; The Sash Window Man’s factsheet describes condition-dependent repairs alongside refurbishment of working parts.[1][2]

Chameleon

• Timber intervention: Chameleon says it cuts out rot, splices in Accoya and laminates the bottom rail, meeting rail and sill in Tricoya, without filler or visible patches. These treatments are excluded from its draught-proofing-only level.[1]
• Working parts: The restoration level includes new cords and weights and freeing stuck sashes; its FAQ adds that new pulleys are fitted where needed. The draught-proofing level excludes these items. The page does not say whether catches are replaced in ordinary restoration.[1]
• Draught seals: Chameleon fits seals around both sashes at every level, including draught-proofing only. Seals therefore do not show that timber repairs or an operating overhaul are included.[1]

The Sash Window Man

• Timber intervention: Its factsheet describes cutting small rotten sill areas back to sound timber and using two-part filler, fitting a glued-and-screwed replacement nosing where the front is rotten, or replacing the entire sill where necessary. Rotten box timber is cut out and repaired with new timber.[2]
• Working parts: Refurbishment includes new sash ropes, checking the counterbalance, oiling pulleys and replacing pulleys that do not run smoothly. The balance check is not a promise of new weights; generally, only broken catches are replaced unless new hardware is specified.[2]
• Draught seals: The Sash Window Man says quotations state whether draught-proofing is included, and customers can request prices with and without it. The treatment uses brush pile at the bottom sash’s meeting rail and, when draught-proofing is ordered, in replacement timber staff and parting beads.[2]

Compare the published prices

Chameleon publishes guide prices for an average-size sash window; it confirms the price after seeing the windows, and the minimum order is five windows:[1]

• Draught-proofing only: £210–£310 a window, £2,100–£3,100 for ten.[1]
• Restoration and repair: from £650 a window, typically £770–£910, or £7,700–£9,100 for ten.[1]
• Restoration plus slim vacuum double glazing: from £1,050 a window, typically £1,050–£1,550, or £10,500–£15,500 for ten.[1]

Chameleon also lists what it says other options cost: £250–£350 a window to repaint and fill, £750–£900 plus £250–£300 painting for joiner patch repairs, and £1,800 in softwood or from £2,500 in hardwood for new windows.[1] Those are a competitor’s figures for alternatives, not quotes from other firms.

Chameleon sends an estimate from emailed photos, which it says is usually within 15% of the final price, then sends the final quote within three days of a visit.[1] The Sash Window Man’s factsheet does not publish prices.[2]

Record faults window by window

Ask both contractors to quote against the same schedule. Give each window a unique label, then record:

• Component and fault: identify the fixed box frame, moving sash or individual part, and describe the fault’s location rather than writing “poor condition”.
• Proposed intervention: distinguish local repair from replacement of a named component.
• Working parts: list cords, weights, pulleys, catches, other ironmongery and draught seals.
• Finishing: identify preparation, priming and final decoration, with responsibility for each.
• Unresolved work: flag anything awaiting inspection or a separate price.

Faults worth recording include soft or rotten sills and rails, decay at the bottom of boxes, loose joints, missing putty, cracked panes, sticking sashes, broken cords, incorrect weights and rough pulleys.[1][2]

Do not let “replacement” silently expand into a whole new window. The Sash Window Man describes separate interventions for sills, box timber and pulleys.[2] Where replacement is proposed, request separate repair and replacement quotations and ask the contractor to explain the condition-based reasons for its recommendation.

For each proposed replacement, ask what cannot reasonably be retained. The Sash Window Man says quotes for sashes identified as beyond repair include making, priming, glazing and fitting them, so confirm any additional finishing costs.[2] Use the schedule as a comparison tool, not as a substitute for the contractor’s inspection.

Choose local repair or component replacement by condition

Ask the contractor to mark the repair boundary: which component is defective, how far the affected area extends, what will be removed and which sound timber will remain. A quote saying only “repair sill” leaves the intervention unclear.

Chameleon’s Accoya splicing and Tricoya treatment differ from The Sash Window Man’s condition-dependent use of small filler repairs, replacement nosings and whole-sill replacement.[1][2] Ask each to explain why its proposed method suits the individual defect, rather than requesting one method throughout the property.

Chameleon’s claims that filler cracks within two or three years and that screwed repairs let water back in are a competitor’s statements, not an independent verdict on The Sash Window Man’s methods.[1] Ask each provider to explain its repair-size criteria and expected service life.[1][2]

A loose joint also need not mean a replacement sash: The Sash Window Man describes tightening joints, potentially with new wedges. Where a sash is already known to be beyond repair, its quotation includes making, priming, glazing and fitting a replacement.[2] Keep that replacement distinct from repairs to the surrounding box and sill.

Specify working parts and draught-proofing

“Checked”, “adjusted” and “replaced” are different commitments. For every window, ask the quotation to distinguish retained parts, servicing and newly supplied components.

• Cords and weights: Chameleon includes new cords and weights in its restoration levels; The Sash Window Man fits new ropes and checks the counterbalance. Ask The Sash Window Man whether any additional weights needed are included.[1][2]
• Pulleys: make servicing and replacement separate entries. The Sash Window Man oils pulleys and replaces those that do not run smoothly; Chameleon fits new pulleys where needed.[1][2]
• Ironmongery: itemise catches, lifts, handles, locks and security fittings. The Sash Window Man lists optional hardware beyond its usual replacement of broken catches.[2]
• Beads and seals: identify replacement beads and seal locations, rather than accepting “draught-proofed” as the complete specification.

Do not transfer promises from a glazing upgrade into an ordinary restoration quote. Chameleon’s vacuum-glazing description includes new weights, cords and locks to carry heavier glass; it may also widen narrow rebates and reinforce weak joints with slim metal brackets.[1]

Specify which sashes should open at completion. The Sash Window Man discourages permanently sealing the upper sash and says its draught treatment cannot be totally effective.[2] Do not treat draught-proofing as a promise of airtightness or assume measured thermal or acoustic performance for the proposed work.

Separate decoration, glass and access

Ask for written entries for preparation, priming and final decoration, identifying internal and external surfaces and who completes each stage. Do the same for glass work, access, disposal and making good.

The Sash Window Man’s factsheet requires final decoration within two months after installation. It describes workshop finishing of new sashes with a microporous paint system; confirm which final-decoration tasks remain yours.[2] Include the agreed preparation and paint specification in the quotation so the finishing obligation is priced alongside the repair.

Its refurbishment procedure includes missing putty and replacement of broken or cracked panes identified in the quote. Long-standing minor corner cracks are left unless replacement is specifically requested.[2] Chameleon says it replaces broken or cracked panes and matches the original glass thickness and texture.[1] Keep ordinary glass repairs separate from optional glazing upgrades.

Chameleon works on site from a mobile workshop, returns removed sashes before night, and estimates five to seven days on site for a house with 15 windows; made-to-order vacuum glass adds 8–16 weeks.[1] Ask how access will be provided and which areas need protection.

Chameleon’s replacement-price wording needs clarification if you compare against new windows: its comparison table lists removal, scaffolding and making good as extra to the £1,800 price, while the accompanying text says the price covers them.[1]

Agree guarantees and hidden-rot charges

Chameleon advertises a 20-year guarantee on its Accoya and Tricoya timber repairs: if rot returns in a repaired part within 20 years, it says it will fix it free.[1] The draught-proofing-only level does not carry that guarantee, and vacuum glazing has a separate 15–25-year guarantee.[1] Ask the quotation to list which repairs are covered, so the guarantee is not read as cover for the whole original window. Chameleon also states £5m public liability cover.[1]

The Sash Window Man’s factsheet offers post-completion help with queries rather than a fixed refurbishment guarantee.[2] Compare the written cover alongside the repair schedule, not the guarantee headline alone.

Hidden decay can also change the scope. The Sash Window Man says a sash found beyond economic repair after work starts may incur an additional replacement cost, and it will speak to the customer before incurring it.[2] Speaking to you is the stated commitment; request written authorisation as an explicit condition for additional work.

For either contractor, propose a variation procedure requiring:

• Photographs or an explanation of the newly exposed decay.
• A revised scope identifying repair or replacement.
• An itemised additional price.
• Your written approval before the extra work proceeds.

Also agree what happens if you decline the additional work. Settle the practical and financial arrangements before dismantling, rather than leaving them to a conversation once the window is open.

What to confirm with each provider

Resolve these remaining gaps before comparing the total commitment:

• Price and timing: ask The Sash Window Man to confirm prices, any minimum order and job duration in an itemised quotation and programme.[2]
• Payment and variations: ask Chameleon to confirm deposit and payment terms and its procedure for rot found after work starts; its repair page does not state them.[1]
• Cancellation and refunds: neither cited document states these terms, so ask both in writing.[1][2]
• Acceptance standards: agree practical checks for sash movement and draught leakage against the specified work; neither provider publishes tolerances.[1][2]

Check property-specific consent before booking

Treat provider consent statements as guidance, not authoritative planning advice. Chameleon says like-for-like timber repairs need no planning permission but that double glazing a listed building needs consent first.[1] Confirm the requirements for your particular property with the relevant authority.

Ask the relevant authority to confirm requirements for the property’s status and the proposed repairs, replacement components, glazing and finish. Do not assume the same answer applies across UK jurisdictions. Agree who will obtain any necessary approvals and settle resulting changes to scope, price or timetable before commissioning the work.

Choose the clearer schedule and agree handover

Consider Chameleon where its specified Accoya splicing, Tricoya treatment, published price level and timber-repair guarantee match the agreed work.[1] Consider The Sash Window Man where its condition-dependent repairs and described operating overhaul match the windows’ needs.[2] The decision rests on the window schedule, including retained components and replacement proposals—not on preserving every part regardless of condition.

Agree handover checks before work starts. Chameleon says restored sashes will slide and balance; The Sash Window Man describes checking that sashes slide before attaching new ropes.[1][2] Use the signed schedule to:

• Try each agreed opening sash and check movement and balance.
• Check specified catches, lifts, locks and other hardware are fitted and work.
• Confirm the agreed seals, timber repairs and glass work are complete.
• Record outstanding decoration, its deadline and who will complete it.
• Collect applicable guarantee documents and record outstanding defects.

Send the same schedule to both providers. Reconcile timber-repair boundaries, hardware, seals, finishing, access and variation terms before deciding which quotation defines the job more clearly.

References

1. Chameleon — Sash Window Repair and Restoration (chameleon-restoration.co.uk)
2. The Sash Window Man — Refurbishing Box Sash Windows (2015 factsheet) (thesashwindowman.com)
3. The Sash Window Man — Repairs in Wimbledon and Wandsworth (thesashwindowman.com)