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3 Top Reasons Why Planning For Annexes Might Get Refused

Deciding as a family to build an annexe in the back garden for elderly parents or a family member is a major decision.

Multi-generation living in the UK is still a relatively new concept and as such our Local Planning Authorities really do not have any framework to work to when it comes to dealing with a planning application to build an annexe in the back garden.

In Australia, Canada and the USA Granny Flats and Granny Pods are in abundance but in the UK with the current UK planning policy guidelines it is not straight forward and should only be handled by a professional annexe planning consultant. (At IHUS we offer this service with every annexe as part of our service.)

Here are the three top reasons we see planning permission refused (based on our experience and each planning application is dealt with on it’s own merits by each Local Planning Authority and the relevant appointed planning officer,).


Why Planning For Annexes Might Get Refused: Reason Number 1

Planning Might Get Refused Because Of The Size Of The Annexe

First and foremost annexes should be ancillary accommodation to the main house.

Our HUSCore range of annexes is designed with this purpose in mind. The annexes we have designed have been developed from our wealth of experience in designing annexes in back gardens over many years.

It is through our extensive experience and working with Local Planning Authorities throughout the UK that we can pretty much determine on our free on site consultation service what is and isn’t likely to be permitted with regards to your ideal annexe design, size and location within the curtilage of your garden.

In general terms your annexe should be:-

  • Subordinate to the main house. (The footprint of the annexe cannot be bigger than the main house.)
  • Ancillary to the main house (meaning that some of the facilities should be shared with the main house. These are usually washing facilities or having main meals in the house with the family.)
  • Should not take up more than 50% of the total garden plot area (front and back) when combined with any extensions you have on the main house. 

Now, everyone thinks their Local Planning Authority are the worst / strictest / least helpful etc but in real terms very few of them have any guidelines to follow with regards to granny annexes and this process is by nature almost doomed to failure if you attempt to deal with this yourself.

It is a sad fact that many granny annexe plans are stopped before they even begin because the main home owner (in all innocence) has contacted their Local Planning Authority for some general advice on whether they could put an annexe in their garden, only to be told “no.”

Today’s Local Planning Authorities are very busy with all the new developments and their resources are stretched to the limit.

Most of them have a pre-planning application option but again unless you have extensive experience with dealing with Local Planning Authorities, this is something best left to the professionals and should carry the warning “please do not try this at home” on it.


Why Planning For Annexes Might Get Refused: Reason Number 2

Planning Might Also Get Refused Because Of The Number Of Rooms

Sometimes this is where the self-builder in you takes over and tries to design a Grand Designs project on a mini-scale.

And in some cases the Local Planning Authority will approve it and others will not.

Planning Applications are dealt with individually, by individual planning officers and is open to interpretation.

An annexe with two bedrooms, a study, full kitchen, walk-in wardrobes, media room and living area may sound fantastic to all concerned, the reality is that most Local Planning Authorities will not consider that type of annexe ancillary accommodation to the main house. (See reasons why an annexe might get refused point #1)

There are many benefits of building an annexe in your back garden and we have two ways of helping you obtain permission to do so.

  • The first is a straight forward Planning Application to apply for planning permission to build an annexe in your back garden.
  • The second is by using the Caravan Act which is applying for permission to site a mobile home in your back garden.
  • In some cases we submit a dual application on your behalf where we deem it to be necessary or where there might be some history of issues with regards to your location or when there might be previous applications that have been refused.
  • You can read our blog post about Granny Annexes and Planning Permission in more detail by clicking here.

When you talk to the experts about annexes and planning permission there is often a solution to your problem that we can help you find.


Why Planning For Annexes Might Get Refused: Reason Number 3

Planning Might Also Get Refused Because Of The Level Of Facilities In The Annexe

This is rarer because most people living in annexes in the back garden need a bathroom, a small kitchen, a bedroom and living accommodation.

Your Local Planning Authority might disagree or have a policy in place that does not allow for a kitchen at all in some circumstances.

I’m sure you are thinking that sounds ridiculous but it’s been found to be true.

The National Planning Policy (to which every Local Planning Authority refers) actually promotes annexes positively in three ways:-

It states:-

There are three dimensions to sustainable development: economic, social and environmental. These dimensions give rise to the need for the planning system to perform a number of roles:

  • an economic role – contributing to building a strong, responsive and
    competitive economy, by ensuring that sufficient land of the right type is
    available in the right places and at the right time to support growth and
    innovation; and by identifying and coordinating development
    requirements, including the provision of infrastructure;
  • a social role – supporting strong, vibrant and healthy communities, by
    providing the supply of housing required to meet the needs of present and future generations; and by creating a high quality built environment, with accessible local services that reflect the community’s needs and support its health, social and cultural well-being; and
  • an environmental role – contributing to protecting and enhancing our
    natural, built and historic environment; and, as part of this, helping to
    improve biodiversity, use natural resources prudently, minimise waste and pollution, and mitigate and adapt to climate change including moving to a low carbon economy.

We believe that Granny Annexes in back gardens support all 3 and are especially important in developing the social role where families are being brought back to live together, strengthening the community and supplying housing requirements to meet the needs of present and future generations.

Another rare but more adaptable restriction we come across is when proposed annexes are in a conservation area or in an area of outstanding natural beauty.

If we are able to liasaie closely with the relevant Local Planning Authority we can usually find the best way to compromise with regards to the materials used such as in the case of our much admired Aldridge project.

Why Planning For Annexes Might Get Refused



  • Annexes might get refused for a number of reasons, even if they do we will re-submit the application as an appeal or under the Caravan Act. Refusals are rare when handled by a professional company such as ourselves as we outsource the task to an annexe planning specialist.
  • Size is by far the most likely reason for refusal, accounting for around 90% of the refusals we have seen.
  • Around 7% of the applications we have managed have beend refused due to the number of rooms / not classed as ancillary accommodation.
  • Around 3% in our experience are declined purely based on the Local Planning Authority’s view on facilities within the annexe and their own guidelines regarding them.
  • It’s very wise to place your trust in a company that deals with annexe planning applications every day rather than try any kind of DIY approach as a refusal will only make everything ten times harder in the future.
  • Annexes in general are accepted by Local Planning Authorities throughout the UK (without exception) and it really is one of those specialised areas that should not be attempted by anyone other than an expert to ensure the right outcome for you and your loved ones.
  • We have a vested interest in your success too.

Feeling inspired? Join us for a no cost, no obligation on-site consultation to explore the annexe options available to you.

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