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Whilst #KSG carries out replacement works on Victorian, Georgian, and Edwardian period properties of all sizes, our surveyors always advise restoring where possible. We are expert historic window refurbishment contractors, particularly focusing on timber sash and casement windows.


In doing so, we breathe new life into the cities beloved historic buildings and preserve the heritage of the properties. 

For a scaffold-free restoration quote, please contact us. 



Manage and minimise risks from traditional window defects

Failure to maintain timber windows can lead to severe structural issues, such as spalling on the exterior sub-sills and water ingress internally. Early remedial action can prevent these problems from escalating and thus save the client from significant repair costs at a later stage.

Kensington Sash can restore your period windows to their original grandeur, keeping your property appearing and performing its best. Without the need for manufacturing lead times, work can be completed in a timely manner. Restoration work does not require planning permission, which is ideal for homes that are either listed or located in conservation areas.

Do your sash windows need repairing?

Sash windows are beautiful period features and add great character to a property. We often find that many of them are old, neglected, and in dire need of an upgrade. If you're questioning sash window repair, please check for the following issues to help determine if it would be wise to proceed with restoring your windows:


  • Draughts and cold spots

  • Rotting timber (important to check sill areas)

  • Windows that are difficult to open and close

  • Damage to/loose fitting locks

  • Broken sash cords 

  • Cracked glass and condensation

It's critical to solve the issues listed above since they can lead to not just a security and safety risk, but also a damp, cold, and uncomfortable property. All areas of timber window restoration are covered by our expertise.

Sash window rot repair
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The basis for all sash window restoration works that we undertake- our sash window draught proofing system is a unique and discrete system rebated into the staff bead, parting bead, and meeting rail of a sash window. This service can reduce air leakage by up to 50% and includes rebalancing of weights and new sash cords as standard. You will notice a vast improvement in the operation of the window itself as well as the benefits of higher thermal performance from the insulation.


We carefully remove all decayed and rotten timber from the window. Our skilled carpenters then replace these routed-out sections with newly spliced in timber matching the original. Small sections are filled smoothly with Timbabuild 2 part system epoxy resin. Once cured, the resin can be drilled, stained or painted just like timber. Sometimes we will opt to replace the whole cill with a hardwood replacement designed to match on a like-for-like basis.

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Where paint is peeling, it is important to redecorate before the exposed timber begins to decay. Our works team uses a range of high-quality finishes when decorating timber windows, which provide essential protection from the elements and improve the lifespan of your products. Decorating your timber windows and doors adds to the curb appeal and overall appearance of your property, and we offer the option of colour matching any Farrow & Ball colour or colours on the RAL chart.


We provide glass replacement services for traditional sash windows and casement windows. We tend to incorporate ultra-slim double glazing units into existing windows that look just like single glazing to retain the character of the original window whilst still improving the thermal performance and acoustic performance. Suitable for architecturally sensitive buildings and those within conservation areas, our units are guaranteed for 5 years for complete peace of mind. For security, we specify toughened options and 6.8mm laminated glass. Please contact our office for datasheets and technical information available.

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We supply high-quality architectural sash window ironmongery in a range of finishes, including but not limited to polished chrome, polished brass, and antique options. Installed by our expert window restoration team.


Are you looking to retain your original windows and/or save costs on full replacement?

We are heritage window replacement & refurbishment experts working on period homes within London.
To request an estimate, schedule a free home design survey, or discuss any aspect of your project with a member of our experienced and professional team please
click here.

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