A Guide To Building A Granny Annexe For Under £100,000

One of our most frequently asked questions we receive is “How Can I Build A Granny Annexe For Under £100,000?”

It’s a great budget to work with and if you follow some of the simple guidelines we’ve set out below you will start to feel confident that it can be done and in most cases it can be done with money left in the bank too.

Granny annexes are a popular way to have a family member living close by but still retaining an element of independence which is vitally important to you both.

As I’m sure your research has shown you so far there are a lot of ways to approach building a granny annexe in your garden and not all of them will serve you well.

Here at Contemporary Log Living we have years of experience of build on site granny annexes and more recently lodge style annexes. Either way there are a few helpful guidelines to follow that will make sure you stick to your budget of under £100,000 for the complete project.


Why Planning Permission Applications May Fail

""granny annexe planning"

Permission to build an annexe in your garden is required no matter what you might read elsewhere and it is a process best put into the hands of planning professionals.

Even a pre-application to your Local Planning Authority done in good faith can damage the outcome for you.

We offer a turn-key service that includes submitting and dealing with your planning permission for you for a fee of just £1900.

We also offer a Certificate of Lawfulness application service if the Caravan Act is your best option for planning success.

Without obtaining the relevant permission to build your granny annexe you run the risk being made to take it down. 

Most planning permission applications fail when you try to take this vitally important part of building a granny annexe in your garden on by yourself.

  • Budget of £100,000
  • Less Planning Fee: £1,900
  • Budget Balance b/f: £ 98,100


Foundations And Mains Service Connections Are Variable

You may like the idea of building your granny annexe as far away from the main house as possible however your Local Planning Authority is almost certainly going to want it as close to your main house as possible for it to be considered ancillary.

A Certificate of Lawfulness allows more siting flexibility but in general, the further the distance the most costly your foundations and mains service connections will be.

Shop around locally for your foundations and services or opt for our turn-key service to get a total package price for your granny annexe project.

Either way anticipate foundations and mains service connections to be anywhere from £5,000 to £10,000 depending on the location of your existing services, and whether you will need additional pumps or updates for mains water, septic tanks or electricity upgrades.

  • Budget of £100,000
  • Less Planning Fee : £1,900
  • Less Foundations and Services (average cost) £7,000
  • Budget Balance b/f : £ 91,100


How To Buy Your Annexe For Under £91,000

"The Beauty of Annexe Living"

If you are building a granny annexe on a tight budget size is a very important factor.

But there is no need to compromise on quality, facilities or price if you choose the right model.

Custom build on site annexes will always cost more than a manufactured model as there are more labour intensive.

Our lodge style annexes are manufactured to BS3632 (British Standards for year round living) and come fully furnished so your budget will stretch a whole lot further.

They also include a range of appliances ready for you to move straight in within a few days of delivery


Two Popular Models That Will Bring You In Under Your £100,000 Budget


The Accolade (A Garden Lodge Option)

"the accolade residential mobile home annexe"

The Accolade is available in two widths, 12 feet wide (3.65m) or 14 feet wide (4.20m) making it suitable for smaller gardens with good access. It comes fully furnished and is a complete ready-made annexe in the garden for a family member without breaking the bank.


The Kielder (A Custom Annexe Option)

"Kielder Custom Annexe"
Kielder Exterior

The Kielder has been specifically designed by our expert annexe team for garden annexe living and boasts one of our most requested features, a front door and entrance hallway in all models. The clever design offers extra storage just where you need it the most.



  • If you have a budget of £100,000 or less to build an annexe in your garden, follow our simple guidelines for success.
  • Always seek professional help with obtaining the relevant permission from your Local Planning Authority anything else is false economy.
  • Choose your model based on size and keep careful control of your budget when it comes to mains services. The further away from the main house, the higher the cost.
  • To maximise your budget choose a lodge style annexe that comes fully furnished and ready to move in. This can potentially save you thousands of pounds in furniture, appliances & furnishings.
  • If you follow these simple guidelines you will have a formula for success that will keep you well under your £100,000 budget.

As with all our residential mobile annexes of this type, it complies with the Caravan Act and requires a Certificate of Lawfulness to site in your back garden. We offer a full turnkey service to help you achieve the best possible outcome without the stress and hassle involved of trying to do everything yourself.

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.

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