Does Your Extension Need Planning Permission?


home extension design plans
contemporary extension conservation area merton

You have to check whether your extension needs a planning consent since if planning consent is required and you start building without having the planning consent, you could be served with a legal notice ordering your home extension to be demolished by the Local Authorities.


The planning permission need is determined by factors such as the size of your build, the Permitted Development rights that apply to your property, and whether you live in a conservation area.


Since the application process might be very complicated, Studio 20 Architects prepared a guide where you can find information regarding extensions. Studio 20 Architects assists your house’s extension plans and assists you with if you need conservatory planning permission (a.k.a. loft conversion planning permission).


In this guide, Studio 20 Architects’ professionals summarized some of the rules about the projects which do need and do not need planning permission.


However, only looking at this guide to understand the regulations concerning extensions and planning application and permission might not be enough, you have to check with professionals such as local planning authority or your architect before you begin with your extension project.

Permitted development rights

The planning law allows some small extensions to be built without having to submit a planning application to your local council is called ‘permitted development rights’. The examples that are subject to permitted development rights are such as some conservatories and loft conversions.


However, the rules regarding permitted development rights are complex and confusing, therefore, a piece of professional advice might be helpful and facilitating. You can find our more information here about the permitted development rights.

new build homes architects
home extension design

Single-storey extension

If you are planning a do single-storey extension, you might not need planning permission to extend a semi-detached or terraced house by eight metres to the rear. There are also height restrictions in single-storey extension projects.


Single-storey side extensions are allowed if the extension is more than four metres