A homeowner is allowed to change both external, internal, floorplans, electrical, heating and even adding an extension on a listed building if the consent has been given. This apply to grade I, II and II* listed buildings, however since a consent is issued case by case, it is not possible to make a general list of things one can do with or without consent.
You are allowed change the following on a listed building if the consent has been given:
- Extension of the House
- Altering the Windows
- Altering the Doors
- Adding New Bathrooms
- Updating the Kitchen
- Renewal of the Roof
- Altering the Area Around the House
- Converting the Loft
- Adding a Conservatory
- Changing the Internal Layout
- Changing or Updating the Fireplace
- Installation of Heating and Electrical Services
The only difference between the grades of buildings when giving consent relies on how much historical material it has inside. This means that a house belonging to grade I may have more architectural and historic features, so the owner might need extra attention on the specialized work to be done. The process may be costly and take more time as well.
What Can You Change in a Grade I, II and II* Listed Building?
The most common types of work that are asked for consent are the following:
Extension of the House
The new extension should not dominate the old building, meaning that it should be lower or smaller. Some small buildings such as lodges and cottages can be easily extended and there is no ideal portion of the increase in size. An extension that is built on the back of the house has less effect on the historic value, side extensions are considered less influential as well. Permission for an extension to the front is rarely given as that is the most visible part of a building.
When connecting doorways for the extension, it is important to not demolish a historic walling and chose an already existing doorway. In some cases, such as medieval timber-framed buildings, removing part of a wall may cause structural problems.
Another aspect that needs to be considered is the matching of the exterior. Choosing complementary materials for walls and roofs is expected when an extension takes place. Contrasting materials in a modern way can be evaluated for some buildings, where the extension can be clearly read from the house.
Windows of an extension need to be double-glazed to comply with the building regulations. It is important to choose aesthetic styles for doors and windows and attention to waterproofing is needed.
It is necessary to search the property history to see if it has been already extended in the past. If it did, then the application for building consent can take place much easier.
Altering the Windows
Windows are one of the aesthetic features of a listed house that characterize its design, material, and workmanship. They can be original or may be altered or replaced in response to the needs. However, if the windows are of historic interest, it is necessary to retain them wherever possible by using matching repair. If repairing is not possible, an accurate copy of the historic material should be made. Any replacement with energy-efficient technologies adapted to the style is well appreciated.
Altering the Doors
Historic doors, both internal and external, play an important role just like windows. The front door or the doors at the front façade are more likely to be considered when applying for consent because of their authentic features. Historic doors should be kept wherever possible, along with their furniture -knob, knocker, and letterbox-.
A wooden door has much better quality than timber doors that are available today. In fact, wooden doors over 100 years old are likely to last more years if they are well-maintained. It is possible to make repairs with a good joiner and ensure to fit well. For this reason, it is required to repair the existing historic door rather than replacing it. Only if the door is seriously damaged, it can be replaced with a matching one.
Adding New Bathrooms
Most houses did not have bathrooms or toilets inside up until the 19th century, and the washing and bathing took place upstairs from the kitchen. As most historic houses were built without bathrooms, they were fitted into bedrooms. For this reason, bathroom works are the most common type of work done inside old buildings. Replacing fittings and refurbishing the existing bathroom do not require any permission and is a straightforward process.
In case of installing new pipes or extra equipment might affect the historic fabric of the house, in this case, the work should be done without cutting into beams or removing the historic timber floors or ceilings.
To deal with problems of condensation and humidity, a bathroom window is necessary to improve ventilation. If there isn’t any, it’s best to be done on a non-historic wall to prevent spoiling the outside of the house. If a new hole is necessary, it should be drilled from the outside to avoid damage to the visible wall. Just like in the cases of windows and doors, any pipe and system should not be placed on the front façade as it would disturb the architectural aesthetic of the building.
If the bathroom has original Victorian or characteristic 20th– century fittings, such as mirrors or tiling, that are listed, it is not possible to remove or refurbish these features.
In case of creating a new bathroom, it is crucial to choose a room that has no important features such as fireplace or plasterwork, unless they can be kept undamaged. It may be possible to cover the historic surfaces with new linings so they can be protected and uncovered in the future. This way the activity can be reversible. Plumbing and connecting the water supply such as boiler, waste pipes can run under floorboards without cutting into the beams.
Updating the Kitchen
Kitchens of the listed buildings may need updating such as replacing modern fittings, plumbing, finishes, and wiring. These works may be straightforward if the remaining features won’t be damaged at all.
When installing new pipework or fitting extra equipment, it’s important to avoid damaging the old fabric such as timber beams or plaster ceilings. The process needs to be easy to reach and reversible, as plumbing and wiring have to be regularly renewed and maintained.
Before starting to work on the kitchen, it is recommended to define the historic features such as bread oven, floor tiles, or fireplace. In order to remove these, a consent is definitely required.
Renewal of the Roof
Roofs have 3 main parts: the timber structure, the outer cover, and the external features attached to the roof such as chimney, finials, and guttering. The roof coverings vary in materials depending on where the building is located and its age. Usually, the clay tile is the most common covering.
Replacing the roof covering may be expensive and disruptive. It is recommended that the owner demonstrates that the work is necessary and effective. The building interior should be protected from damp that can be caused by defects in chimneys or slipped slates.
When talking about updating the terrace of a listed building, the biggest concern lies in the efficiency in meeting the distinctively historical taste with individual housing in an urban context. The terrace must be adaptable in meeting the individual needs, hence match the original materials as closely as possible.
Materials that match both in appearance and physical characteristics will react the same way over time. For the owner to apply for Building Consent, he/she must provide the plan form of the regular terraced house.
Altering the Area Around the House
Most old buildings have a backyard or garden or a front yard to separate the building from the street. These areas add interest to the building and are also included in the building listing.
The garden is an important element of the landscape. The boundary walls, paths, gates, railings, and even trees can be considered as the historic features of the house. For altering this area, old photographs and maps should be provided and the process can be carried out by the conservation area appraisal that can provide more information.
For a new parking pace, a planning permission, and impermeable materials such as concrete are necessary. It is important to carefully plan this area as it may lead to flooding.
Redecorating the House
The external decoration can improve the house’s appearance and visual aesthetics while protecting it from the weather. A regular redecoration of the outside is important, and it helps prevent decay. This is specifically needed for the external woodwork such as windows and doors that need regular painting every year to protect the wood from weather and sun. The hardwood can be an exception as it is best to leave it unpainted, but oiling or traditional treatment may be necessary occasionally.
External coatings can be renewed with special breathable paint such as limewash that protects the material but prevents moisture as well. In old houses, extra attention needs to be paid to moisture in walls to avoid damp. Painting brick, stone, or concrete walls can create damp problems and modern paint materials are almost impossible to remove without causing damage. It is strongly advised to pay attention to the wall paints when applying for consent.
Traditional colors for the house are recommended as they reflect the character of the building. However, the toxicity level of some traditional paints means that they are restricted by environmental legislation. For this reason, it is better to check the paint legislation of historic buildings of your authority. In some conservation areas, there are special controls on the colors chosen.
The internal decoration on the other hand gives the owner the opportunity to make the most of the original features and bring out the history. Any decoration that protects the house or updates the history may have consented. If the house has early wall decoration, the owner may need specialist advice and conservation rather than just decoration.
Any kind of stripping activity on lime and plaster is not recommended as it may remove layers of history that can’t be reversed. Stripping finished on woodwork, either painted or bare, is considered as damage to the historic elements of the house.
Original features such as wall-paneling, picture rails, and timber moldings around doors and windows need consent to be removed and may be costly.
Converting the Loft
When thinking about converting the loft, the linked aspects such as the roof and the interior of the house must be taken into account as well. The roof of a listed building may have features on it as well. There are 3 aspects: the roof timbers, the loft space, and other roof features.
Finally, it is necessary to check the condition of the roof in case the owner may need to repair it as part of the conversion work. The owner must demonstrate solid reasons as a roof tends to last a long time and not get affected by changing fashions, unlike room decorations or windows.
Adding a Conservatory
Adding a conservatory is another type of extension of the external layout of the building. A light-filled and quick element may be accepted or denied depending on the location, size, materials, and design. Also, the conservatory must meet standards for energy efficiency and insulation.
Another aspect that needs to be evaluated carefully is the location of the conservatory. Even though it may get better sunlight, a conservatory should never be constructed on the front façade of the original building. The side and rear are usually the best locations.
It is important that the conservatory does not dominate the view and the choice of material must be carefully evaluated in relation to the existing building.
Changing the Internal Layout
The internal layout is one of the most important characteristics of a listed building and it can be a major undertaking. The layout describes the size and shape of rooms, position of the doors and windows, where the rooms are connected, and where the stairs are located.
The layout is a major obstacle as in the most historic buildings it indicates how it was first built, may have changed over time and how the living standards have improved.
A good step to start with is to understand how the original plan was and how it altered over the years. The owner should work on the plan of the house by marking the original parts and separating them from the more recent ones. When thinking about internal alterations, it is usually better to work with the historic grain of the building. This allows them to maintain the main rooms and stairs in their existing positions.
Removing internal walls to make larger rooms or dividing a large room to make smaller spaces are the most common type of internal layout works. However, it is expected to keep the old walls, or at least show where they were before.
Changing or Updating the Fireplace
Fireplaces have 3 main parts: the chimney breast, the hearth, and the chimneypiece. When deciding on whether to remove or refurbish the fireplace, all the components must be carefully examined and consented to.
The chimney breast is part of the structure of the building, in fact, it strengthens the structural wall. Removing it for creating space in the house may arise new problems. The flues inside the chimney breast help ventilate the house, if the chimney breast is removed, this may also create ventilation problems.
A chimneypiece is part of the history and design of the house, it tells how the room was used throughout history. Quite often, a chimneypiece is one of the original fittings of a listed building and has a visual focus. Removing it for sale is often rejected by authorities as it would damage the history of the house forever.
Converting the grate to gas or electricity may be done if the process is reversible for the historic materials. If the owner wants to have any kind of live fire, he/she must keep the hearth slab.
Installation of Heating and Electrical Services
Installation of heating or electrical services is one of the most common types of work in listed buildings as they usually fall behind the modern living environment. It should be noted that the owner may not be able to use the shortest or most direct route for electrical systems or pipework.
The owner may wish to install, replace or upgrade heating and electrical services to comply with health and safety regulations. Electrical services such as lighting and power for communications, data, fire alarms, and security systems may be added to the building. Other types of furnishings such as oven, dishwasher and washing machine can be included as well.
Air conditioning, radiator heating, toilet fans, and other mechanical services that upgrade the house and living environment are accepted in the building consent process.
How to Do Changes in a Listed Building
Listed buildings are the backbone of the cultural heritage. For this reason, it is important to preserve their architectural significance according to the compliances of law. However, this does not mean that the building must stay in its original condition. As a matter of fact, the local authorities encourage owners for several implications to make their properties more livable. This way, these buildings can be traded in the market while preserving their values. In fact, Historic England states that:
“Listed buildings are to be enjoyed and used, like any other building. Listed buildings can be altered, extended and sometimes even demolished within government planning guidance” adding that “The local authority uses listed building consent to make decisions that balance the site’s historic significance against other issues, such as its function, condition or viability.” 
Regardless its grade, it is possible to give consent to a listed building if the changes to be done are planned according to the “principles”, as defined by the local planning authority. These imply doing extensive research of the building and documentation; planning changes that don’t cause damages and can be reversible; and finally, recording these changes for future use.
It is important to do the first research before starting to think about the changes. The owner should consider the historical and architectural aspects of the property.
It is recommended that any alteration, addition, or repair done to the concerning building are capable of being reversed. This can minimize the impact of the work on historic material and ensures the original plan of the building.
Any kind of work that reveals undiscovered information about the building should be recorded and reported to the authorities. It is essential to provide a copy of the findings to the local records in order to be archived so future generations can share this information. 
How to Get a Listed Building Consent
The Planning Permission applies to all kinds of buildings; for Listed Buildings, other forms of permission are required additionally. As any kind of change made in a listed building affects its special interest, it is essential to get a Listed Building Consent primarily.
According to the building’s grade, the owner must get an outline of what might be acceptable and find out alternative ideas that can be adapted to make them more likely to succeed. This operation can save a lot of time and money.
When the planning authority considers the application, it gives particular attention to the principles mentioned above. This means that it looks for implementations that preserve the building’s value. These are things that the owner must think about when he or she is planning to propose changes.
Before applying for a Listed Building Consent, it is advised to carefully read the guidance from relevant pages of the local planning authorities. 
What Can’t You Change in a Grade I, II and II* Listed Building?
The cumulative impact of having done lots of changes in a house, even though some are small, can be significant. For this reason, it is important to minimize or if possible, remove the likelihood of complete alterations of the buildings, especially caused by works during building services.
Any work that neglects the 3 principles of Building Consent cannot be accepted by law. It should be noted that any unauthorized work is a criminal offense and may be charged with fees or prosecution. 
Grades of Listed Buildings
A listed building means that the building retains a particular feature of the surrounding area or nation’s value. In the UK -and the rest of the world-, listed buildings are grouped in 3 main categories according to their particular importance. As a result, the higher the building’s grade, the more there are restrictions.
Grade I buildings are of exceptional national, architectural or historical interest. These are mainly buildings built before the 18th century and have very characteristic features. Grade I buildings may have more features in detail that require extra specialized works for alterations.
These are particularly important buildings of more than special interest.
Grade II buildings are of special interest that still need to be preserved. These concern the majority of buildings in the heritage list. Grade II buildings are more common in the real estate market, and it may be perceived as easier the make changes in this group.