Granny Annexe Planning Q&A

Granny Annexe Planning Q&A!

We recently posted a Granny Annexe Planning Q&A on Social Media and received lots of questions.

We know that whether you’re considering an annexe for ageing parents, adult children, or extra living space, navigating the annexe and mobile home planning application process can feel overwhelming. But fear not, we’ve got the answers to your most frequently asked questions to help you get started.

1. How long does the planning application process take?

Typically, the planning application takes 8-10 weeks after the validation period. Here’s a simplified breakdown of the process:

  • Weeks 1-3: Your local planning authority (LPA) informs relevant parties like neighbours and councils about your plans. They have 21 days to submit any comments.
  • Weeks 4-8: A case officer assigned to your application will review it and potentially conduct a site visit.


2. How much do application fees cost?

The fee depends on the project. For a granny annexe, the application fee is £328 including the planning portal surcharge. You’ll pay this directly to your LPA.

3. How high can my annexe be if it’s within 2 metres of the boundary?

The maximum height allowed is 2.5 metres.

4. Do I need permission for a garden room with sleeping space?

Yes! Introducing sleeping accommodation takes your garden room outside the scope of permitted development, meaning you’ll need planning permission. This is because it becomes ancillary (secondary) to the main house, rather than incidental (minor).

5. How can I increase my annexe application’s chances of success?

Here are some key tips:

  • Location:

    • Keep the annexe close enough to the main house for easy access
    • Ensure it doesn’t significantly impact neighbours’ privacy or enjoyment of their property
  • Size & Design:

    • Make sure the annexe is proportionally smaller than the main house
    • Design it using materials that complement the surrounding architecture
  • Facilities: Limit the built-in amenities to keep the annexe basic and secondary to the main house.

By following these tips and consulting with planning professionals like NAPC, you could significantly improve your chances of a successful planning application.

Have more questions?

Get in touch using our book-a-call form, or email us below. We’re here to help you navigate the granny annexe planning process and turn your vision into reality.

Further reading

We have a whole section of our website dedicated to annexes, and planning permission, here are just a few.


Get an answer quicker with a Feasibility Study

A one-off Feasibility Study (from £99) will equip you with crucial planning insight about the area you’re planning to site your Annexe or Garden Room. So if you pursue your application, you have the best chance of success. 

Prefer to talk to a planning expert in person?

Book a call with one of our planning experts or call/email us directly.

Phone number

01285 283200


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