single storey extension

Single Storey Extensions

At The Extension Experts we offer a complete range of architectural and surveying services. Specialising in preparing all the drawings necessary to get your extension built, we produce all the information needed for Planning and Building Control (Building Regulations), as well as for your builder to actually build your extension.

We have extensive experience working with almost all London Planning Departments and Building Control Departments and understand exactly what is required and what will, and what will not, get planning approval. This allows us to consistently achieve a virtually 100% first time approval rate for single storey extension planning applications in London, the South East, and surrounding areas.

We start with an initial meeting with yourself at the property to discuss what you require and to get an idea of what is needed to ensure your project is a success and as stress-free as possible. We can ascertain from this inspection such things as whether planning is required, if any other specific works are required such as new water, gas, or electricity connections, whether there are any specific constraints, and we can advise on all other potential obstacles that you will need to tackle in order to legally get your single storey extension built, such as Party Wall issues for example. It’s also an opportunity for you to decide whether you want to work with us!

Following the consultation, we will provide you with a quotation for our services which is a fixed-fee for the whole project. Our single storey extension fee will include a full measured survey of your property, as well as everything that you require in terms of architectural and planning input for the entire project. The only other thing you will need is a builder, and again this is something we can help you with should you be looking to find a local, reputable contractor.


To summarise, our single storey extension service includes the following key steps:

  • Initial consultation to discuss your proposals.
  • Issue of a fixed-fee quotation for your consideration.

Following acceptance of our fee we will then start work on your single storey extension, which includes:

  • A full measured survey of your property
  • Preparation of all drawings and other documentation necessary for your local Planning Department
  • Drawings and notes necessary for Building Regulations, including structural calculations.
  • Unlimited revisions to the design to ensure it meets your requirements.
  • Submission of the planning application to the Planning Department.
  • Managing and overseeing the application with the Planning Department through to approval.
  • Following Planning Approval from the Planning Department, we will then advise you as to when you can start building your single storey extension.
  • We will also review progress on site with your builder to ensure they are building your single storey extension in accordance with the approved design.



The price we charge for our single storey extension service varies greatly dependent on the size and complexity of the project, and therefore we always come to visit the property and discuss your plans before providing a fixed price.

However, to give you an idea of a typical fee for our complete single storey extension service, we would recommend allowing between £950 – £1,450 excluding VAT.

This is a fixed-fee and allows you to carry out as many revisions as you would like and includes all the information, drawings, and surveys required to get Planning and Building Regulations approval.

If you have any questions regarding our fees please do not hesitate to contact us.


Customer care is at the heart of what we do and we take pride in ensuring that the wants of our customers come first. Our primary objective is to make building your single storey extension as stress-free as possible and provide an exemplary and professional service that gives you peace of mind from the start.

At the end of our projects we often request feedback from our customers. Here is just some of the feedback we’ve received from our customers:

“Absolutely could not have asked for any more. Your team turned the project around much quicker than anticipated and whilst we were slightly daunted by the planning process you made it so much easier for us than we ever thought it would be. Thank you for your help over the past few weeks / months.” Amanda Laverack, Sundridge Park

“You were a pleasure to work with and I really appreciate all of yours, and your teams, hard work. We will definitely put in a good word for you to anyone looking for an extension in the area.” – Clive S, Chislehurst

“We were all very impressed by the work you did for us and pleased with the final result. Thanks again!” Richard M, Chislehurst


Areas covered

We work throughout London and the South East, as well as in parts of Kent, Sussex and Surrey. We also work further afield depending on the size of the project. If you are unsure if your area is covered then please do get in touch.

We carry out single storey extensions in: Barking, Barnet, Bexley, Brent, Bromley, Camden, Croydon, Ealing, Enfield, Greenwich, Hackney, Hammersmith, Fulham, Haringey, Harrow, HAvering, Hillingdon, Hounslow, Islington, Kensington & Chelsea RBKC, Kingston upon Thames, Lambeth, Lewisham, Merton, Newham, Redbridge, Richmond upon Thames, Southwark, Sutton, Tower Hamlets, Waltham Forest, Wansdworth, Westminster, Kent, Surrey, Sussex.

Book a consultation

If you’re planning a flat conversion you can request a consultation using the form below and we will be in touch with you shortly.