Home improvement – have you considered building an annexe?

If you’re currently looking into extending your home, have you considered an annexe?

Whatever your circumstances, should that be teenagers, young adults or elderly parents, an annexe could potentially provide a nice mix of independence whilst still being located within close proximity of your home.

What is an annexe?

An annexe is a self-contained living space, often just an en suite bedroom and a living room. They can often include a kitchen space. Basically it allows the resident to live completely independently.

What kind of costs can I expect to pay for an annexe?

Costings to build an annexe can vary hugely. Obviously specification is a major factor; so expect to pay anything between £1,500 to £2,500 per square metre. Bear in mind that other variables such as connection services can affect the costs, so also allow a contingency for unexpected items at construction stage.

And don’t forget to add fees for planning permission, building regulations, architects and other consultants when you’re budgeting, often between 10-15% of the construction cost overall.

Do I need planning permission for an annexe?

You will usually need planning permission to build a habitable annexe in your garden, although limited extension of an existing house to create an annexe may fall within permitted development rules without the need for an additional approval.


You would benefit from working with an architect to create a bespoke scheme for your property before applying for planning permission. They will have the knowledge and skills to help you with your project, as they will know what’s allowed for your property type, whether you live in a listed building, or within a conservation area or some other designated area, and what the various options are.


If planning permission is granted for an annexe, it is likely to include conditions that restrict occupation of it to members, guests or dependents of the household, and will also prevent the separate sale of this part of the property.


Is there Council Tax exemption for annexes?

You cannot claim Council Tax exemption on an annexe but you can claim a reduction, under certain circumstances. These include if the annexe forms part of a single property, which includes at least one other dwelling, and is being used by a resident of that other dwelling or one of those other dwellings, as part of their sole or main residence. Find out more on the government’s website