14 minutes

Steps to Success: Replacing Windows in a Grade II Listed Building

One of the most common queries in the context of listed building architecture is whether window replacements are permitted. In this guide, we hope to inform our readers of the steps to success in changing the windows of a listed building. We will look at the rules and regulations surrounding replacing existing windows in Grade II listed buildings and the easiest way to make the changes possible.


As a listed building owner, you are likely aware of the need for planning permission from your local planning authority to make any alterations. This is also true for the case of replacing windows and doors in a listed building since these features are considered to be vital characteristics of historic interest. With this said, by following the correct process and ensuring that you adhere to the laws and regulations surrounding listed building and planning consent, you should be able to make the desired changes.

Whether you wish to install double glazing or replace timber windows, we outline the steps below and what you need to do. No matter the grade of your listed building, it is important to follow the rules and laws in place.

How do I check if my home is a listed building?

There are many listed buildings throughout the U.K., and the Historic England website makes it possible for you to search for listed building information. The National Heritage List for England includes all listed properties.

You can also use Historic England to check your proximity to other conservation areas. This is very useful as it will determine the likeliness of getting approved for planning permission.


How long does it take to get planning permission?

Many factors should be considered when obtaining planning permission to change windows. As you likely are already aware, it is often not a short process. The type of application can determine the processing time significantly, larger and more complex developments require more time for assessment. Pre-application advice is another area where Graded building owners should take their time. Before formally submitting a planning permission application to replace old windows, you will need to identify any potential issues with the help of a local planning officer.

Once a planning permission application has been submitted, the timeframe in which it is processed depends on the local planning authority’s efficiency. The responsibilities of a local authority are vast, and sometimes processing times are affected due to this. There is also sometimes the need for a public consultation, where the public can make any objections to the proposal known. This can also extend the time it takes to obtain planning permission.

In scenarios where an Environmental Impact Assessment is required, this can also add to the processing turnaround. EIAs are an assessment of the environmental effects of projects. After this step, negotiations and amendments may be requested, depending on responsiveness and flexibility this can also result in a more streamlined, and time-effective process.

Finally, if planning permission is denied and you wish to appeal, the process will be prolonged. Engaging with the local planning authorities early in the process and providing a well-prepared planning application can contribute to a more efficient approval process.

What happens if you alter a listed building without consent?

If you carry out any alteration works to a Grade II listed building without listed building consent, you are breaking the law.

The consequences of extending or altering a listed property without planning permission can be very serious. Local authorities have the power to take legal action against you which can result in fines, court orders, and in serious cases imprisonment. Where a listed homeowner carries out work without planning permission, they are commonly ordered to undo alterations to restore the building to its original state. This can be a time-consuming and extremely costly process.

Listed Buildings Window Restoration & Double Glazing – Reglazing Guide

One of the most common reasons people choose to replace the windows of a listed building is heat loss and dampness. These are two issues that are highly associated with older buildings, as window technology has vastly improved over the years. Though it may seem like a straightforward request to install double-glazing in your listed home, it is very difficult to be granted planning permission for double-glazing of Grade II listed building windows.

Windows change the fabric of a property’s historic character and for this reason, many councils will disapprove of double glazing. Older buildings generally feature more distinct types of glass windows, including sash windows and timber windows to name just a couple.

Glazing options are individual to building types and for many historic buildings, double glazing is not an option due to gap sizes. A conservation officer must assess the practicability of double-glazing and reglazing your listed building’s windows. This is because double-glazed windows are typically between 22 and 28mm thick, whereas traditional glass windows are usually only 2-3mm thick.

As you can imagine, this makes it almost impossible for original windows to be replaced with double glazing due to the strain that will be put onto the old frame and glazing bars of listed buildings.

Where a historic property does not feature significant glass windows considered to be of historic interest, a double-glazed window may be permitted. We offer a free consultation call for any architectural queries regarding listed homes.

Listed Building Window upgrade options


Should I Replace Or Repair My Listed Windows?

Preserving the historical and architectural integrity of your listed property must be a priority, if you fail to do so, you could face a planning enforcement notice. Conservation Officers always favour repair work over replacement work to listed properties, this also applies to window frames and new windows.

In many cases, when careful and precise window repairs are carried out, authenticity and function can be balanced. If your building has windows where the damage is more extensive, a replacement is likely required. Windows in listed buildings should only be repaired by skilled specialists who have experience in working on historic windows.

Below, we have put together a list of considerations to help you decide the best course of action for your Grade II listed building windows.

Deciding whether to repair or replace Grade II listed windows involves careful consideration of various factors to ensure the preservation of the building and the conservation area’s historic character. Here are some key considerations:

Assessment of window condition

You cannot decide on the best option to replace windows without assessing the overall condition of the existing windows. If the older windows still remain structurally sound and damage is localised, repairing may be a good option. In the case where extensive deterioration is clear, a replacement is likely warranted.

Historical significance

Next, you should assess the historical significance of the windows and the existing windows and frames. This involves thinking about how they contribute to the overall historic interest of the building. Windows are often integral to a building’s heritage, this is why repair and conservation are often preferred.

Authenticity of materials

For window replacements or repairs, you will always have the consider the authenticity of the new materials used. Original materials can be preserved through repair, which is generally more applicable to Grade II listed homes.

Architectural Features

This is where a heritage architectural designer’s insight is very useful. You will need to examine the architectural features of the windows which include the glazing bars, mouldings, and any decorative elements. Preserving these features will influence the decision of whether a repair or replacement job is best.

Planning permission

Planning permission is required by law in the U.K. if you wish to make any changes or repair any elements of a Graded building. This includes initiating work on windows.


Repairs can sometimes be more cost-effective than replacing old windows. Heritage windows may only require minor repair work, in such cases, long-term considerations should also be made to avoid ongoing maintenance costs.

Energy Efficiency

Modern double glazing is one of the most effective ways of keeping our homes warm, unfortunately, historical windows are not very energy efficient. Where improving this area is a priority, you may be able to combine repairing a window with secondary glazing, for example.

What are your glazing options for a listed building?

Despite an emphasis on repairing windows rather than replacement windows, there are still options for glazing windows in listed buildings. We have made a comprehensive list of possible options for you below.

Secondary Glazing

Secondary glazing is a process which involves adding a layer of glass on the interior side of the existing windows. This option can increase energy efficiency and offer further insulation without the need to alter any of the external characteristics of a listed home.

Slimline Double Glazing

Slimline double glazing is where a thin layer of double glazing is installed in the existing window frames. This can be preferable for Grade II listed homes as it provides some of the benefits of a modern double-glazed unit without affecting the outside appearance.

Heritage or Conservation Glass

There are heritage window specialists who offer conservation glass to replicate the traditional design of windows in historic buildings. This is a more costly option but will ensure that the original appearance of the building is maintained.

Timber Sash Windows

In cases where the original building had timber sash windows, replacing them with a replica timber sash is an excellent option. Modern glazing techniques can be incorporated into these traditional-looking windows.

Beware:The wrong windows can hurt the value of your home

Windows play a crucial role in a property’s aesthetics, functionality, and energy efficiency. Not using like-for-like materials or choosing the wrong style of window can impact property value, especially in the case of installing modern windows in Graded homes.

The wrong windows can also affect energy efficiency, which is another consideration. Outdated windows can be less effective resulting in higher utility costs, this can deter potential buyers.

To maintain your home’s value, you should consider architectural style, materials, and energy efficiency whilst aligning your choices with the original character of the building. Changing windows in a listed building can have serious financial implications, so an informed decision is advisable.

When To Repair a Sash Window?

Sash windows are a type of window typically found in properties dating back to the 17th Century. These types of windows originated in Holland and are a traditional type of window that consists of one or more movable panels, or ‘sashes’ that form the window frame.

If your listed building features these heritage windows, you may be considering repairing the windows rather than a window replacement. Here are some examples of when a sash window may need repair:

Difficulty opening and closing the window – Sash cords, pulleys, or the window frame can become damaged over time. Repairing or replacing these components can help improve functionality and make it easier to open and close the window.

Decayed or damaged wood – Rotting and decaying wood is one of the main reasons for window repairs. Check the window frame, sashes, and sills for signs and repair early on to keep the structural and characteristic integrity of the window intact.

Draughts and air leaks – At the first sign of a draught coming from traditional windows, investigate. If you notice any sort of air coming into the building, gaps in the sashes may be present.

Broken or loose glazing – Modern double glazing rarely comes loose or breaks, however, the same cannot be said for sash windows. If glazing putty becomes loose or gets cracked it can reduce glazing efficiency.

Condensation between panes – Where there is condensation between sash window panes, a broken seal is likely the culprit. The seal will need to be replaced to restore insulation.

General wear and tear – Over time, listed building windows suffer damage naturally. Therefore, it is wise to enlist the help of a heritage officer who can advise on when to repair your sash windows.

Like-For-Like Windows in Listed Buildings

The historic features of a Grade II listed building and your respect for them will greatly influence as to whether a planning officer will approve works. When writing a planning application, you must demonstrate how you will protect the features of the historic building. With this said, it does not always mean that modern materials cannot be used. Sympathetic replacements are sometimes agreed upon, particularly where energy efficiency and the comfort of living in a listed building are impacted.

With this said, ‘like-for-like’ windows are always preferred where replacements are being installed. Like-for-like replacements ensure that the new windows closely match the original design in terms of materials, style, and details. This consistency is essential for preserving the overall aesthetic of the building.

Consult Our Specialist Heritage Architectural designers 

For expert guidance and assistance in navigating the complexities of window replacements in Grade II listed buildings, Christopher David Design can assist. We can provide invaluable insights and support tailored to the unique challenges posed by Grade II listed properties backed by our experience of working in heritage conservation. Contact us to begin your consultation and make your project a reality.

Christopher David Design & Listed Buildings
We're extremely fortunate to work across many listed and national heritage building projects, with each being completely unique.
Our complete approach encompasses specialist skills and careful planning to ensure our clients' a result they are proud of. In the case of preserving and protecting listed homes, a specific step-by-step plan must be put into place.

Below, we've covered some of the most common questions Christopher David Design receives in relation to our approach to listed building projects.
If I'm Planning To Renovate A Listed Home, What Are The First Steps?

Begin with research first. Many people who fall in love with listed buildings may find themselves disheartened when they’re unable to freely renovate the building to their wishes.

The local Conservation Officer who will review your application for Listed Building Consent will look at the details. It’s also a good idea to look at what changes have taken place across the property in the past.

If previous works have been undertaken to renovate the historical property, there will be more flexibility for you to do so. Once you’ve carried out your research you will be in a better position to plan on what is going to be an achievable renovation project for your listed property.

Who Should Be Involved In The Project At The Beginning?

We highly recommend involving a team of specialists right from the beginning of your project. In addition to architectural designers, conservationists and heritage consultants are key in ensuring the project is a success.

Conservationists and heritage consultants thoroughly understand the special approaches that are required for renovating listed properties. They will also be able to advise on the materials that should be used to maintain the building’s original character.

What Is The Architectural Designer's Role In Supporting Through The Process?

Listed building architectural designers bring everything together – from the initial design stage right through to completion. From the larger scale decisions to the more minor, Christopher David Design oversees every aspect while supporting other professionals in their roles too.

What Sort Of Process Does Christopher David Design Offer Its Clients?

Our main priority is to pay respect to the historical architecture of a listed building. Every listed building renovation project should aim to maintain a property’s original character and charm. We carry out an initial assessment to understand the historical aspects of the property before liaising with a planning officer.

Once this first step has been taken, we put together a considered design proposal that is sensitive to the historic fabric of the property. All of our listed building projects are approached in a way so that any renovation work complements the original build.

We look at how to best maintain features and where the replacement of repair works or additions is necessary. It is important to remember that designing takes time and quite often it involves negotiating, especially in the case of listed buildings.

However, it is completely possible to renovate a listed home to create an outcome that you will love while paying respect to a building’s heritage.

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