Planning a granny annexe requires consideration of: the nature of your home, tax and financial implications, and long-term suitability.

Planning to move your parents or other elderly relatives into your existing property can be a challenge. However, it can have significant benefits in terms of being able to provide better care, and can reduce the need for a care home in the future. The current UK government has also recently announced changes to Council tax payments that will reduce the tax burden for housing extra family members.

The advantages of creating a granny annexe include:

  • Closer proximity and reduced isolation for your loved one/parent
  • An ability to keep an eye out for signs of poor health
  • Increasing the value of your property

How to plan a granny annexe?

There are a lot of options, and almost as many problems to consider. But careful planning can maximise the benefits while minimising the stress.

  1. You need to consider the suitability of your existing property for extension.
  2. Work out how this impacts upon the financial and tax implications in terms of location, size and value of your property.
  3. You need to consider the design and layout of the annexe so that it meets and continues to meet the needs of your parent or loved one over time.

Remember, if you have young children, you can move your elderly loved one into an additional bedroom space, like a garage conversion or garden structure, for the time being. As your children get older and your elderly loved one becomes more frail, it might be possible for them to swap accommodation. This might allow an older child more privacy for study away from the bustle of the house, while moving your elderly relative for closer supervision.

Your current property and what you need to consider

Do you have:

  • The potential to extend
  • An existing garage space
  • A pre-built structure in the garden, like a summer house, that with slight planning permission could be converted

Will the building work functionally? Can heating systems be extended? Can water supplies be provided?

Bear in mind that it’s easier to extend water supplies when they’re placed either adjacently or directly above or below existing water supplies. For example, bathrooms are usually placed above or beside kitchens so that the water supply can drain through the same waste pipe. If you’re unable to achieve this with your current property layout, an additional waste option may have to be added, or you may need to consider a fallout pipe that will join your existing waste through an extended connection that slopes slowly downwards. This option is perfectly viable, but the gradient will need to be enough to avoid repeated blockages.

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Garage conversion

If you have a garage space that can be converted, this will mean there is easy access from a part of the property that feels relatively separate, but is also based on ground level and would not incur any extra council tax charges.

Extensions and summer houses

Building an annexe in the garden is potentially an option if you have less space inside your property, but you will need to gain planning permission if the floor space is more than 30 metres squared. If the size is less than this, the same rules apply as with a garden shed. The disadvantages are that you would need to arrange plumbing, electricity, central heating and other amenities to the annexe, which may be costly. Unless you are willing to wait for planning permission for a larger annexe, space may become a problem, particularly if in the future your elderly relative requires more care in the form of wheelchairs or carer access.

Design considerations

It’s important to consider the medical needs and sensory impairments of your elderly relative in terms of the location and layout of the annexe. For instance, depending on their needs, you may need to install wider doors, lower door thresholds and potentially allow room to manoeuvre a wheelchair.

What about specific conditions such as dementia? If your elderly relative is prone to wandering, you may need to consider whether the annexe is enclosed or whether there will be access to a public road.

It is also important to consider independent living technologies and ‘age in place’ best practice, such as providing bathroom facilities with grab rails and lower, smoother handles for kitchen furniture. Installation of Wifi can allow for the use of new digital services that help families care for their older relatives.

Tax and financial implications

The government has recently published changes to council tax banding and removal of the infrastructure levy. These are significant benefits for families looking to save money by moving elderly parents into their property.

Council tax implications

Many families benefit from living in properties with self-contained annexes that allow them to house or care for extended family members. The current Council Tax system unfairly penalises those with family annexes through double taxation – householders are billed a second time for the annexes in addition to their payment for their main property. A national discount for all family annexes (not just those for older people) has been proposed, as a quick and easy way to remove this Council Tax surcharge from the system, saving an average £485 a year on a typical £2,427 combined yearly bill.

Removal of infrastructure levy

The government is also confirming that it intends to remove the community infrastructure levy on self-build properties, including all extensions, family annexes and home improvements. Ministers also intend to seek to remove Section 106 housing levies on such annexes and extensions – a ‘stealth tax’ slowly being introduced by town halls.

Added value

The annexe can add value to the property, make it more saleable, as well as providing increased support and proximity to your elderly relative.

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Home care

Even if you bring your elderly relative or loved one into your home, you may be unable to provide care for them full time. Whether through work commitments or through the emotional strain that some specific conditions can cause, home care can provide the flexible support you need.

HomeTouch is an online introductory agency based in central London. We connect families looking for care, with local self employed carers. You can search on the site for a carer who suits the needs and personality of your loved one. To search for a self-employed carer near you, type your postcode into the search box below:


Dr Jamie WilsonFounder and Chief Medical Officer at Hometouch

Dr Jamie Wilson is hometouch’s founder and Chief Medical Officer. Jamie’s creation of hometouch was inspired by his work as a dementia psychiatrist in the NHS, and he has written about healthcare issues in The Times and the Evening Standard. Jamie has a MBBS from the University of Leeds and has spent a decade in the NHS, working as a Psychiatric Registrar and Memory Specialist at Imperial College Hospital.

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