Whether raising the height of an external door requires planning permission depends on the location of the door, location of the property and how drastic the height change will be.

For smaller changes to the side and rear of the property, permitted development rights may apply, meaning no application or planning permission is required.

Where the height change will be substantial and have a significant impact on the building’s appearance, planning permission is likely to be required. Especially in cases where the door to be heightened is on the principal elevation of the property.

‍Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

In designated areas such as conservation areas, or on listed buildings you may require additional approvals such as listed building consent.

If you believe permitted development rights apply to a small change, you can apply for a lawful development certificate to ensure this is the case.

Building regulations

Building regulations approval will likely be required where the change impacts the structure of a building, this primarily occurs when an opening is widened. When altering walls you may want to consult a structural engineer.

Land and buildings are categorised by their type and purpose through a system known as ‘use classes’. A 'Change of use' can be within the same Use Class or from one Use Class to another.

You can find a full list of use classes and change of use scenarios related to planning on the Planning Portal website.

Read more about use classes

Installing patio doors at the rear of your house is likely to fall under permitted development rights, meaning an application for planning permission is not required, provided certain limits and conditions are met.

The doors should be of similar appearance to those previously used, if they are not then generally planning permission will be required.

If you live in a listed building, you will need listed building consent for any significant works.

If you live in a designated area such as a conservation area or national park, then additional restrictions may be in place.

If you are unsure whether the work falls within permitted development rights you can check with your local planning authority or submit a lawful development certificate to prove the change is lawful and prevent any future enforcement action.

‍

There is no single legal definition of "habitable room", as its use and meaning are subject to context. Generally, a habitable room is a space in a building that is designed for people to live, sleep, or spend extended periods of time in, but does not include bath or toilet facilities, corridors or utility rooms.

By law, any planning permission granted expires after a certain period. Generally, unless your permission says otherwise, you have three years from the date it's granted to begin the development. If you haven't started work by then, you will probably need to reapply.