Sash windows refurbishment

Sash window refurbishment with no unsightly patches after restoration. Sash Windows Repair with Guarantee for 8/15/20 years.

Sash windows refurbishment

Sash window refurbishment

Traditional wooden sash windows like all wooden items, they need special attention and regular maintenance to keep them in good condition. Because wooden windows are exposed to elements, their life span can become short without proper restoration and maintenance.

Let’s look at available sash windows restoration routes:

Decorating route: Quick repairs with epoxy fillers

For many decades homeowners have been using decorators to paint and protect sash windows. The expectations towards such work, like the standards themselves, have never been too high. It is already a common practice to have timber windows repainted every three years.

Windows assesment uk
Windows assesment

What price do decorators charge to paint the window

The average cost of 1 wooden window repainting is £200-250. This does not include any repairs. If a window needs minor repairs, the price for wooden windows repairing and painting its exterior side is around £270-£350. It is worth knowing that such patch wooden window repairs will not last longer than 2-3 years at best.

Short maintenance cycle of old sash windows

A typical 3-bedroom house has 10 windows, and a house owner would have to pay circa £3000-3500 every three years just to maintain windows, not to mention the time-consuming exercise of finding decorators, collecting quotes, arranging the work, dealing with delays and inevitable disruptions to your life of having tradesmen working outside of your house but still walking in and out. This is still a reality that many households in the UK exist.

Repairing old sash windows: Local joiners route

However, in the recent few years a new service emerged – When people are looking for “sash window repair near me” services, they usually find a sash window refurbishment company. Such companies usually originate as joiners or builders, people who know a thing or two about windows. They renovate wooden windows by cutting out damaged areas and replacing them with new pieces of wood screwed into frames or window sills. Any rotten parts are removed and are then filled with DryFlex, a two-component wood filler. Such repairs look significantly better than simple patch repairs. However, they, too, have their flaws.

Screws will move with the timber movement (shrinking and expanding when the temperature changes), pushing the screws and fillers up, damaging paint and leading to further wood decay when moisture gets in.

Also, these repairs are always visible when you look at a freshly repaired window. Some people accept this as an inevitable evil, others seem to accept these flaws as the character of old windows. Such sash windows renovation with or without servicing pulley and cords may cost anything between £550 and £700 per window (you need to add £200-220 for painting). This work is certainly not cheap.

decayed cutting in restoration

Sash windows replacement route

There is another, more radical option: complete sash window replacement, softwood sash window will cost you from £1600 per window, hardwood from £2500 per window.

The best thing about this solution is that the windows will look new. However, not for a long as softwood sash windows will start to rot in 5 years (look at the photo from one of our recent surveys below). In 8-10 years, expect to have two maintenance cycles on this new window, one re-decoration and one re-decoration + repairs.

windows replacement route
Softwood sash windows after 5 years.
new sash window after 5 years
new sash window after 5 years (softwood)

First, is a huge cost, accounting for removal and disposal of existing windows, cost of the new windows and glass, their installation, rental of scaffolding, painting the windows inside and outside, making good and painting damaged walls.

If a house is listed or is in a conservation area, a house owner would need to jump through numerous hoops of getting a permit to replace it.

Our sash window refurbishment method

At Chameleon, we renovate all types of wooden windows and provide a 20-year guarantee on all repairs with Accoya/Tricoya wood and an 8-year guarantee on paintwork, which means no redecorating for the next 8-10 years after we refurbish windows.

sash window refurbishment
Example of our work

We use a combination of traditional sash window renovation with a lamination technique.

Together they allow us to refurbish wooden windows back to their former glory without changing their look, with no patches and complete peace of mind for decades to come.

We price our timber frame refurbishment work at £689 and retrofitting at £1679 per average size window.

You can read about what is included in each service and how they are different here.

sash window spliced repairs
sash window lamination

A window will look the way it was first installed – no messy and uneven old paint, no signs of repairs, just clean lines and smooth surfaces with a window that is protected for decades.

With our lamination method we can turn your old soft or hardwood timber frame window into the window with rot resistant properties equivalent to window made of Accoya timber.

sash window frame repair
window repair in uk

Window restoration using the lamination method

What does thorough timber window restoration and lamination look like?

We remove all decayed and damaged timber, sand most of the paintwork down to bare wood, and protect affected areas with wood hardener. The repairs are done with flexible wood fillers and resilient timbers, like Accoya and Tricoya, without any screws.

The whole length of a damaged rail is then laminated with Tricoya timber.

Tricoya man-made timber is guaranteed to last up to 30 years in the ground and over 50 years above ground, unprotected. When properly protected, it will last for as long as the house stands. This is the type of protection that will withstand even the harshest rains and the most dramatic temperature changes.

Sash Windows Repair
grade 2 listed building lamination

Lamination is widely used in construction and other industries like flooring, furniture production, and car manufacturing among others. Laminating with Tricoya allows us to achieve an excellent level of timber protection without a heavy price tag.

Our method of renovating utilises our engineering background, joinery, carpentry and decorating skills. Some of the tools we use in our work we made from drawings, others were customised for the processes involved. Each repair is individual, yet follows strict guidelines to achieve the highest quality and protection for the windows.

Sash window services

4 Steps to repair and upgrade your old sash window
4 Steps to repair and upgrade your old sash window 

Alternative to traditional putty

We repair and replace the missing putty with epoxy sealants. They are flexible, yet thoroughly stick to glass and timber, protecting the wood from moisture. No putty or beading could ever hold the glass and protect woodwork better than epoxy sealants. Under a coat of paint, they look identical to putty, keeping the historic look of the windows intact.

Sash windows paint spraying

Once all surfaces are properly protected and prepared for painting we then use paint sprayers. Paint sprayers apply an equivalent of up to 8 coats of paint when applied by brush. Here is the detailed guide to our exterior windows painting.

The paint coat is thick and even. The paint we use is flexible and allows for timber movement. The paint itself and the thickness of the coat applied thoroughly protect the woodwork from any possible natural damage.

brush paint layers
paint sprayer layers of paint

Also, when applied by a paint sprayer, the paint dries fast and the windows can be shut the very same day, making the inconvenience of keeping all doors and windows open all day and night a thing of the past.

Listed sash windows repair

Our renovation methodology is suitable for grade 2 listed buildings and those in conservation areas

Our method of renovating historic sash and casement windows is approved by conservation officers who regularly oversee our projects. Sash window renovation does not require any permission as it preserves and protects the original features of a historic building.

At Chameleon we do all of the above work – renovation of historic wooden windows, draught-proofing, slim double glazing and spray painting. We are a full-service company for the preservation and thermal efficiency of historic wooden windows.

Double glazing original sash windows

Rebates and weak frames in heritage sash windows

Old wooden Sash or Casement windows are always a challenge when it comes to existing sash windows double glazing. Rebates (a gap where a glass pane fits into) in such windows are quite narrow. Standard double glazing would simply not fit into such rebates. Also, frames need to be strong enough to carry the extra weight of double glazing.

Retrofitting of Double Glazing

Originally they were meant to carry the weight of a single glass. Installing double glazing into such frames will make them dangerous to operate. To make things even trickier, sash windows with a system of weights and pulleys need a competent adjustment to make sure the extra weight of double glazing does not impact their smooth operation. We work with Fineo glass. It is only 6.7mm thick, yet excels the thermal performance of a standard size triple glazing unit. It is an excellent choice for period properties. For windows with very narrow rebates, we have a tailor-made solution.

Not only do we widen such rebates, but also strengthen frames with slim metal frames strong enough to keep roof joists together so the windows can carry the extra weight of glass units and never again produce cracks at the joints. All these alterations are inconspicuous and will not alter the look of historic windows.

For sash windows, we add weights, change ropes, and replace locks where necessary to ensure the windows work in a safe and smooth manner.

FINEO vacuum-sealed double glazing

Fineo glass is a new product on the market. It is less than a year old but is gaining wide popularity for its slim profile and excellent thermal efficiency. A slim double glazing unit exceeds the thermal efficiency of a standard-sized triple glazing unit. It is manufactured by AGC in conjunction with Panasonic in Europe.

Fineo has a market-leading 15-year guarantee. Most slim double-glazing systems only have a 5-year guarantee due to their use of inert gases, which escape over time, leading to loss of thermal efficiency. The Fineo glass is vacuum-sealed, making it more thermally efficient and robust.

Chameleon official FINEO glass installeer

Because of Fineo’s depth of only 6.7mm, it can be used in historic wooden windows with very slim rebates.

However, it is important to make sure that the frames are strong enough to carry the extra weight of the new glass. If the frames need strengthening, this must be done by specialists. These are rare, even among slim double glazing companies. We have such sash window renovation specialists at Chameleon. They will be happy to assess your double glazing project and provide tailor-made solutions for your windows.

If you live in an area with a high rate of house break-ins, you may want to consider installing reinforced slim double glazing. Just like standard slim double glazing, it will keep the historic look of the house, will be equally thermally effective and will protect your house from burglars. The company announced the production of its reinforced glass will begin in 2022.

Listed windows double glazing retrofitting

Double glazing retrofitting for Grade 2 listed buildings

Historic wooden windows need minor but very important adjustments before slim double glazing can be installed. Widening rebates and reinforcing frames are the most important adjustments.

We do them inconspicuously to comply with current regulations. This makes it possible for historic buildings to have windows renovated, double glazed and protected for decades to come.

Sash window draught-proofing

As part of our sash windows repair and double glazing projects, we do draught-proofing. Draught-proofing is one of the most effective ways to save energy and money in any type of building.

Controlled ventilation helps reduce condensation and dampness, by letting fresh air in when needed. Comprehensive draught-proofing can save up to 10% on energy bills.

Sash Window Draught Proofing
Read more

Ideally, draught-proofing should be done together with double glazing to maximize the energy-saving and reduce heat loss in houses to bare minimum. When done together with window renovation and/ or double glazing, draught-proofing will be almost twice cheaper than if done alone.

These jobs have many processes in common and create a significant saving for a homeowner not just on the energy bills but also on the cost of the work. However, if double glazing is not an option or you already have it and want to improve energy efficiency further, draught-proofing is the best solution to keep your home warm.

draught proofing sash windows


What kind of wood do you use?

In our timber window restoration projects we use Accoya and Tricoya wood.

Do you repair windows on Grade 2 listed buildings?

Yes, we regularly work with Grade 2 listed buildings and conservation area properties. We do like-for-like timber frame repairs. They do not require planning permission as we do not change the look of the windows.

Can you unblock stuck or painted-shut windows?

If your sash windows are stuck or painted shut we can unblock them, either by removing the problem paint during the restoration process or by changing sash cords, pulleys and rebalancing weights if needed to return windows to full functionality. We do these core repairs as a part of larger window restoration projects.

Can you replace broken glass panes?

We can replace broken or cracked glass. We also ensure that the new glass thickness and texture match that of the original glass.


Our projects

    Sash Window Refurbishment in Hertfordshire

    Sash Window Refurbishment in Hertfordshire

    Sash windows restoration in Suffolk

    Sash windows restoration in Suffolk

    Thin double glazing installation in St. Neots

    Thin double glazing installation in St. Neots

    Retrofitting original sash windows with double glazing in Suffolk

    Retrofitting original sash windows with double glazing in Suffolk

    Rotten Casement Windows Restoration near Cambridge

    Rotten Casement Windows Restoration near Cambridge

    Fitting double glazing to existing windows in Chelmsford

    Fitting double glazing to existing windows in Chelmsford