Increasing the size of a window will often fall under permitted development rights, meaning an application for planning permission is not required to make the change, provided limits and conditions are met.

Any new window must be of similar appearance to the original which you are replacing.

Permitted development rights do not apply to flats. To increase the size of a window in a flat or maisonette you will require planning permission.

 If you live in a listed building, you will require listed building consent for any major changes.

Where the work has as significant impact on the external appearance of the house, especially on the principal elevation, planning permission may be required.

Building control 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.

Building control will also consider energy efficiency, glazing, ventilation and fire safety.

A designated area is situated within a World Heritage Site, Conservation Area, Site of Special Scientific Interest, National Park, or an Area of Outstanding Natural Beauty, the area is protected by law due to its architectural or historic interest or landscape.

Due to this protection, there will be further limits on what you can do to your property if it is within such an area, for example building an extension, changes to the roof, or work to trees. Restrictions will be put in place and permitted development rights will not apply.

If you live in a designated area, you must seek advice from your local planning authority before starting any work.

Permitted development rights allow certain types of work to be carried out without the need to apply for planning permission. It typically covers things like small extensions, loft conversions and outbuildings, provided they meet specific size and location limits. These rights can vary or be removed in areas like conservation zones and by Article 4’s, so it’s best to check before proceeding.  

Read about permitted development and Article 4 directions on Planning Portal

‍

Categorising land and buildings according to their type and purpose is known as Use Classes.  

A 'Change of use' can be within the same Use Class or from one Use Class to another.

You will need planning permission for certain changes to the use of a property such as changing from a residential use to a business use. However, it is possible to change use between some classes without having to make an application for planning permission.

Depending on the specifics of any proposed change of use, including any building work associated with the proposal, an application for planning permission or prior approval may be required.

Planning permission is not required for the installation of a stair lift, however, if you live in a listed building, you will have to apply for listed building consent for any significant works, whether internal or external.

Stairlifts must be installed in line with BS EN 81-40:2020 which focuses on safety requirements for the installation of stairlifts.