Double glazed listed building, Isleworth London

Replacement sash windows on listed buildings are commonly Victorian or Georgian, each with their own unique design and character.

Whether you’re looking to repair or replace your sash windows, there are many things that can be done to accurately replicate the design and finish of your windows, to maintain the historic architecture of the building and ensure planning permission is granted.

Sash windows with glazing bars

Because any changes to listed buildings need to be approved by planning officers, restoration or part replacement is often preferred and easier to get approved than full replacement. Restoration usually involves, for example, installing draught proofing, de-glazing and re-glazing, or replacing sections of damaged wood.

Part replacement usually involves replacing the moving sashes (or casements) while retaining the window frames, if the frames are in good enough condition to be saved. This is a popular choice for listed and conservation properties, particularly replacing single glazed sashes with double glazed sashes, to improve insulation while retaining as much of the original architecture as possible.

Whether the sash windows need to be partly replaced or fully replaced, planning officers will want to check that the replacement windows will replicate the originals faithfully enough, before granting planning permission. Fortunately, listed windows experts such as Timbawood specialise in creating elegant windows that are regularly approved.

Hand painted sash windows

For example on Georgian properties and earlier, rather than a single pane of glass, sash windows would have been made with several smaller panes joined together with glazing bars. The panes would have been glazed into position using putty, rather than the timber that is used today, and the glass would have had a slightly uneven surface rather than the modern flat look.

At Timbawood our sash windows can feature ‘restoration glass’ which replicates the uneven look of the original glass (and can be laminated for extra safety and security). The windows can be individually glazed and include a hand-puttied, hand painted finish to complete the heritage look. And most importantly, we carefully exact-match the original design of the profiles, mouldings and glazing bars.

In over 25 planning authorities throughout London and the South East our windows have been approved which feature slimline double glazing – as it looks just like single glazing and therefore doesn’t compromise the look of the building. This means we can vastly improve the efficiency of the windows without affecting the elegant lines of the architecture. The outer pane of the double glazing can also be made with traditional looking restoration glass.

Sash window repair & replacement

Are you looking to repair or replace your sash windows, without compromising the look of your property?

Timbawood is a London based sash window company, specialising in sash windows repair, sash window replacement and part replacement for period, conservation and listed properties. Many of the projects that we work on, such as the Grade II listed ‘White House’, top, involve a complex mixture of replacement, part replacement and sash window repair.

Whether single or double glazed, our sash windows are characterised by their slim profile sections, fine mouldings and slender glazing bars, combining understated design with modern technology – including the latest in high performance timber and paint systems.

As experts in period, conservation and listed properties we also make bespoke timber casement windows, French doors, Front doors, bifold doors and internal doors. 

If you would like to speak to one of our experts about your listed building project, please get in touch.

You will need to apply for Listed Building Consent to make any changes to windows on listed buildings – for more information on this have a look at our guide on how to get planning permission to replace windows on listed buildings, or the guidance for listed buildings from Historic England.