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Where do I start with planning a single storey extension? How much should I be paying for architects plans?

I live in an average sized semi detatched house. I am planning a small single storey extension at the side of my house (approx 10m square) to extend my kitchen. I have done some research on the internet and looked at previous questions on here, but it’s actually thrown up as many questions as it has answered!!
I’m not sure where to start as I don’t know exactly what I want (just a kitchen extension or a smaller kitchen extention and separate utility room?) I don’t know whether to get some building quotes first for a rough estimate or get plans drawn up first (will architects actually give me advice on what to have done or do I need to tell them exactly what I require?)
Also, I’m unsure if I need planning permission because although the extension is only small it will be going right up to my garden boundary. Do architects advise on this? (I don’t want to pay for plans only to find I can’t build what I want to).
On that subject, roughly how much would plans cost from an architect? (also, I’ve read on other websites that you can use a technician instead of an architect to produce plans. What is the difference?)
I understand the concept of planning permission, but I also keep reading about planning notices, certificate of lawfulness and building regulation fees. What are these and do I need them, or are they covered by planning permission if I get that?
Roughly how long will all this take, and how long to build the extension itself? (I am looking ahead to how much time I will need to take off work to be at home whilst the building work is carried out)
Sorry there are so many questions, but any advice on any of my questions would be appreciated. I will be looking for quotes from tradespeople on this website once I am ready to go ahead with this work (hopefully this April/May/June time)
Thanks very much, Janice



Here are some tips on where to start with planning a single storey extension:

  • Speak to your local authority’s planning department first to understand if you need planning permission. They can advise based on the size, location and height of the proposed extension.
  • If planning permission is needed, then it’s best to hire an architect to draw up professional plans and submit them for approval. Expect to pay £500 – £1500+ for architectural plans, depending on the firm and complexity.
  • Technicians can do basic layouts but architects understand regulations better and can provide guidance on optimal design. Use architects for submitting official plans.
  • A certificate of lawfulness confirms an extension meets standards and doesn’t require planning permission. This costs a few hundred pounds from your local authority.
  • Building regulations approval will be needed even if planning permission isn’t. This ensures structural integrity and safety. Fees are a few hundred pounds.
  • The whole process of planning, approval, finding builders and constructing a 10m2 single storey extension could take 2-4 months minimum if things run smoothly.
  • Get quotes from builders early so you understand rough costs. Architects can also provide ballpark estimates. Consider your budget and time limitations.
  • Work with the architect to decide what layout and features you need. They can advise on optimal size, access, flow etc based on your goals, budget and property limitations.

I’d recommend starting with your local planning department, then engaging an architect as they will guide you through the entire process from design to approvals.

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