- 13 October 2026|
- News|
Crittall windows can be one of the defining features of a period property. Slim steel frames, narrow glazing bars and large areas of glass give them a distinctive appearance that is difficult to reproduce with many modern window materials.
But after decades of exposure to the weather, even durable steel windows can start to show signs of wear. Rust, flaking paint, draughts, stiff casements and damaged glazing can leave homeowners wondering whether their original windows have reached the end of their useful life.
The good news is that age alone does not mean your Crittall windows need replacing. In many cases, restoration can bring old steel windows back into good working order while retaining their character. Where frames are beyond practical repair, bespoke replacement windows can provide a new solution that respects the proportions and appearance of the original installation.
Why Crittall windows are worth understanding
Crittall windows have played an important role in British architecture for more than a century. The story began in 1849, when Francis Berrington Crittall acquired an ironmonger’s business in Braintree, Essex. His son, Francis Henry Crittall, later developed the company’s metal window manufacturing business, helping establish steel windows as a practical choice for residential buildings.
The Fenestra joint, introduced in 1909, allowed Crittall to produce stronger, slimmer frames with larger expanses of glass. A new factory opened in Witham in 1919, while Crittall windows became closely associated with modernist and Art Deco architecture.
Francis Henry Crittall also helped establish Silver End, the model village near Witham. Many of its homes featured Crittall steel windows, while the development was influenced by his son Walter Crittall and remains an important example of early modernism.
Crittall Windows Ltd continues to manufacture steel windows today. Many original installations from the inter-war period remain in homes across the UK, helping explain why their durability and distinctive aesthetic appeal remain popular.
Signs your old Crittall windows need attention
Steel windows are known for their durability, but they still need care. Moisture, damaged protective coatings and years of use can gradually affect the frame and its components.
Common signs include:
- Rust or corrosion showing through the paint
- Flaking or deteriorating coatings
- Casements that stick or are difficult to operate
- Draughts around opening lights
- Worn hinges, stays or handles
- Cracked or damaged panes of glass
- Condensation around single-glazed windows
These problems do not automatically mean the window needs replacing. Surface corrosion may be treatable and damaged hardware may be replaceable without removing the original frame.
The condition of the steel itself is more important. A detailed assessment can establish whether the existing frame is suitable for restoration or whether deterioration has gone too far.
Can old Crittall windows be restored?
Yes, many older Crittall windows can be restored rather than replaced. Historic England’s guidance on historic windows recommends considering repair before replacement for historic windows, particularly where existing windows contribute to the character of a building.
At Metwin, our Crittall window restoration service is designed to bring existing steel windows back into good condition while retaining as much of the original installation as possible.
Depending on their condition, restoration can include:
- Assessing the existing frames and components
- Removing the windows for restoration where required
- Removing corrosion and old coatings
- Repairing damaged steel sections
- Hot-dip galvanising
- Applying a protective powder coating
- Reglazing and reinstalling the windows
We can also supply genuine Crittall parts for older installations, making it possible to repair individual components rather than replacing an otherwise fine window.
When does restoration make sense?
Restoration can be a good option when the main frame remains structurally sound but has developed surface corrosion, damaged coatings or worn components.
It can be particularly important where the windows are original to a period property. Retaining historic fabric can help preserve the appearance and character of the building and may be preferable from a conservation perspective.
When should old Crittall windows be replaced?
Replacement may be appropriate when existing frames are too badly deteriorated or distorted to restore effectively. Extensive corrosion, damaged sections or previous alterations can sometimes make restoration impractical.
Replacement can also be considered where homeowners need a different specification to improve the performance of their windows.
The important point is that replacement should follow an assessment of the existing windows rather than simply being based on their age.
Where replacement is appropriate, we can manufacture bespoke steel windows to suit the dimensions, configuration and appearance required for the project. This allows details such as glazing bars, opening arrangements, sightlines and finishes to be considered as part of the design.
What does replacing old Crittall windows involve?
Replacing your windows is a significant project, particularly in a period property. Understanding the process can make it easier to plan the work.
1. Initial consultation
We discuss the property, the condition of the existing windows and what you want to achieve. This helps us determine whether restoration, replacement or a combination is most appropriate.
2. Site assessment
We assess the existing openings and take the measurements needed for the proposed windows. Where heritage or conservation considerations apply, these can also be considered.
3. Design and planning
The design can take account of the original glazing bar arrangement, proportions, opening configuration, hardware and finish. Where planning or conservation requirements apply, these should be established before work begins.
4. Manufacturing
Once the design and specification have been agreed, the replacement steel windows are manufactured to the required dimensions and configuration through our manufacturing service.
5. Installation
Our installation team removes the existing units and fits the new steel windows, taking care to achieve an accurate fit and finish. Find out more about our window installation service.
6. Aftercare
We can continue to support your windows through our service and maintenance offering. Genuine Crittall parts are also available for older installations where replacement components are needed.
Can replacement Crittall windows match the originals?
This is often one of the biggest concerns for homeowners. Replacing an old window should not mean losing the character that made it suitable for the property.
Details such as glazing bar patterns, proportions, sightlines, opening arrangements and finishes can all be considered during the design process.
Crittall’s HomeLight range uses a small profile designed to preserve the look of original Crittall windows while providing improved energy performance. Its styling reflects the typical Art Deco design of the 1920s.
For unusual dimensions or layouts, our bespoke steel windows provide greater flexibility. This can be particularly useful when a replacement needs to sit naturally within an older property’s existing architecture.
What about double glazing?
Thermal performance is often one of the main reasons homeowners consider replacing old single-glazed Crittall windows.
Modern glazing can reduce heat loss, but the most appropriate solution depends on the existing frame, the condition of the window and any conservation requirements.
Historic England’s guidance on modifying historic windows notes that slim-profile double glazing can sometimes be introduced into historic windows, although its compatibility with the existing frame needs careful consideration. Secondary glazing can also provide an alternative where retaining the original window is particularly important.
The performance of any window upgrade will depend on its complete specification and the property itself.
At Metwin, we offer Crittall systems with modern glazing options, including double glazing, allowing thermal performance to be considered alongside the appearance of the window.
Do you need permission to replace Crittall windows?
If your property is listed or located within a conservation area, check what permissions apply before replacing or significantly altering the windows.
Replacement windows in listed buildings can require listed building consent. Historic England’s listed building consent guidance explains when consent may be required and how the process works.
Properties in conservation areas may also be affected by additional local controls. An Article 4 Direction can remove permitted development rights for certain changes, including window replacement. Historic England’s guidance on permission for older homes explains how these controls can affect homeowners.
The safest approach is to contact your local planning authority before work begins. You may also need to consider Building Regulations, depending on the nature of the work.
At Metwin, we have specialised in listed buildings and conservation area projects since the 1990s. Our site assessment and design process takes the requirements of the property into account from the beginning.
How can you tell whether restoration or replacement is right?
There is no single answer for every old Crittall window. Two windows that look similar can be in very different condition.
As a starting point, consider:
- Surface corrosion: This may be treatable through restoration.
- Damaged components: Replacement parts may allow individual fittings to be repaired.
- Severe corrosion: Steel sections that have deteriorated extensively may make replacement more practical.
- Distortion: A badly distorted frame may be difficult to restore effectively.
- Historic significance: Original windows may be particularly important to retain in a listed or historic property.
- Thermal performance: Modern glazing may offer improved performance where the existing specification is inadequate.
The best way to make the decision is to have the existing windows professionally assessed before committing to replacement.
Speak to us about your old Crittall windows
Old Crittall windows do not necessarily need to be replaced simply because they are showing their age. In many cases, careful restoration can extend their life while retaining the character of the original installation.
Where replacement is the better option, bespoke Crittall steel windows can retain the slim profiles, glazing patterns and architectural character associated with the originals while introducing modern performance.
At Metwin, we have specialised in listed buildings and conservation area projects since the 1990s and are an approved Crittall Specialist Partner. We offer restoration, manufacturing, installation, maintenance and genuine Crittall parts, giving you one specialist team to support your project.
If your Crittall windows are rusting, sticking or letting in draughts, contact us to discuss your options and arrange an assessment.