Can I Have A Brick Granny Annexe?

One of the most frequently asked questions we get is about the possibility of having a brick granny annexe.

For some people the idea of living in an annexe is a “proper little home” at the bottom of the garden and that means a brick built granny annexe is what they have in mind.

The fact is of course it can be done. 

Annexes are typically constructed on-site as either a timber-frame insulated building (like a new home) or with SIPS (structurally insulated panels) (a modern day construction method that is designed for strength and speed of construction.)

The main differences other than that are:-

  1. As an annexe is classed and built as a mobile home (saving you thousands of pounds in VAT by the way), the foundations are usually screw-piled or on a concrete plinth system. This is to allow for an annexe to be considered a temporary building and not a permanent dwelling. 
  2. The exterior cladding is often timber (such as Western Red Cedar) which requires maintenance every 2-3 years or cement based weatherboard cladding which is widely used in commercial construction today and typically comes with a 50 year guarantee. (It’s also low maintenance and available in a wide choice of colours and finishes.)

So why is it that you don’t see more brick granny annexes?

Read on to find out the top 3 problems associated with building a granny annexe in brick and one possible solution that may suit you.


1. Planning Permission Is Very Unlikely To Be Granted For A Brick Granny Annexe

Granny annexes are classed as ancillary buildings to the main house, not a separate dwelling.

There must be “a link” to the main house and can only ever be sold as part of the main property.

Your Local Planning Authority will control this use via the conditions they will apply to any permissions they grant for the annexe to be built.

Your Local Planning Authority is highly unlikely to grant permission for a separate dwelling in your back garden.

And contrary to popular belief (thanks Google) ALL granny annexes require permission of some kind to be built whether they are classed as mobile homes or not.

You will need either a Certificate of Lawfulness or Householder’s Planning Permission to build an annexe in your back garden.

Both are only available via your Local Planning Authority and this is a service we offer on your behalf as part of our turn-key services.

Without the relevant permission you simply cannot build a granny annexe.

2. It Will Cost You At Least 20% More Than A Regular Granny Annexe

"bella vista mobile home annnexe"

If you are thinking of building a brick built granny annexe it will not be classed as a mobile home for VAT purposes and therefore become 20% more expensive to build because your builder will have to charge VAT @ 20%.

Your Local Planning Authority will have a policy about what they refer to as backland development (which is a very specialised area best dealt with by Planning experts.)

However it covers 2 main areas that would be affected by a brick built granny annexe in your back garden.


Access typically refers to existing and future residents of your area, access for emergency services, cyclists, cars and pedestrians and lead to more cars being parked on the street etc.


Any annexe (whether it is a brick granny annexe or not)will take into consideration your neighbouring properties to all aspects of your property and garden.

Considerations for them will include impacting their privacy, daylight, sunlight, outlook and light polution.

Neighbour objections are common with granny annexes as it always highlights people’s natural concerns about something that might affect their lives.

If you are in an area of outstanding natural beauty, green belt or a conservation area planning permission is likely to be even more difficult for a brick granny annexe.

Location will also be a significant factor plus any precedents that have already been set within your area.

Always consult an annexe planning expert before you dive in and get carried away with your brick granny annexe plans.

Annexes are not self-building your own home in your back garden.

An annexe is an annexe.

3. Why Not Build An Extension Your LPA Might Ask?

"rear extension ideas"

In the UK today there is high demand for homes.

That’s why the Government has set targets of 1 million new homes by 2020 and no doubt you have thousands of new homes currently being built near you right now?

I know we do here in Shifnal in Shropshire (there are hundreds in what used to be fields all round us!)

So surely one brick granny annexe in the back garden isn’t going to hurt anyone? Right? 😅

Unfortunately your Local Planning Authority may well have no objection to the Government demanding build schedules for the most part (some do get refused by the way) but might well object to your plans to build a brick annexe in your back garden and issue a refusal.

That’s the nature of planning in the UK and why it should be handled in the right way from the start.

If you are thinking of building a brick granny annexe give careful consideration to building an extension instead and using up your permitted development rights to the full.

“But I want to be separate to the main house I hear you cry!”

And therein lies one of 10 of the Biggest Mistakes Most People Make When Thinking About Buying An Annexe (which we’ve turned into a handy little PDF download for you)

"0 Big Granny Annexe Mistakes"

One Possible Compromise That Might Suit You If You Have The Budget

"granny annexe prices"

If you have come this far and lost heart with building a brick granny annexe we may just have a silver lining for you.

Providing your Local Planning Authority is perfectly OK with the concept of building an annexe in your back garden and it ticks all the boxes for them:-

  • Ancillary to the main house.
  • For family member use now and in the future.
  • There is a need (elderly care for example).
  • Link to the main house (eg. service connections)
  • Built as a mobile home (not separate dwelling).

They might consider allowing your external cladding to be brick slips. This will give the appearance of brick on the outside but satisfy your Local Planning Authority that it is indeed a granny annexe.

The downside to using brick slips is the added cost.

You will typically need to add £8,000 to £10,000 to your budget for this type of exterior cladding finish.

If you are completely lost and don’t know where to start Book A Free On-Site Consultation With Us.

We’ll help you decide whether annexe living is right for you, help you come up with a floor plan, size and budget and help you choose the right way to go about annexe building from the start.

It’s a win / win!

"Book A Free On Site Consultation"

We consider ourselves to be the best free advice you’ll get anywhere in the annexe sector and if you have a question, please feel free to contact us on the website or on our Facebook page if that’s easier for you.


  • Brick built granny annexes are extremely rare because they are classed as separate dwellings by your Local Planning Authority.
  • Brick built granny annexes also attract VAT @ 20% as they are not considered mobile homes.
  • You can get a brick built exterior appearance by using brick slips cladding but again, the cost will be much higher than with a traditional granny annexe build.

Choosing The Best Way To Live In Your Back Garden Starts With Understanding What Is Possible.

A residential mobile home annexe like the one featured above can be sited your back garden with a Certificate of Lawfulness. Click here to view more from our range.

As always we look forward to your thoughts and comments below or join in the conversation on our Facebook Page !

Use The Contact Us Page To Email Us With Your Enquiry

Pete Cossie, Contemporary Log Living

Sharing is caring!