There are two requirements before you begin your project. The first of these is Planning Permission, which is whether you will be allowed to build it or not. An extension or major alterations to your existing house will usually require planning approval from your local authority planning department.
Some projects are classed as “Permitted Development” and do not require planning permission. For example, planning permission may not be needed if the extension is single-storey, to the rear of your existing property and within certain dimensions.
You can get additional advice on this from your Local Authority planning department or the Government’s DCLG web-site by following this link ……
https://www.planningportal.co.uk/
…or better still, give me a ring for more information, or email me from my ‘CONTACT’ page.