A garden annex for an elderly parent can be a good option where some independence remains but living close to family matters, particularly where round-the-clock medical care isn’t needed. It gives a parent their own front door, their own space and their own routine, while putting them a short walk from the people who love them rather than a drive away. Whether it’s the right choice depends on the level of support your parent needs now, and how easily the design can adapt as that changes.

What does a garden annex offer an elderly parent?

The idea often gets shorthanded to “granny annex,” but that undersells what’s actually being built. A well-designed annex is a genuine home: its own kitchen, its own bathroom, its own front door, built to the same standard as the main house. For an elderly parent, that distinction matters. They’re not moving into a spare room or an outbuilding. They’re moving into a self-contained space they can call their own, while staying close enough to see grandchildren after school or share a Sunday lunch without anyone getting in the car.

For many families across Sussex, Surrey, Kent and Hampshire, this is what starts the conversation in the first place. Not a single crisis, necessarily, but a slow accumulation of small worries: a parent managing alone through a difficult winter, a fall that could have been worse, a phone call that goes unanswered for a few hours too long. An annex doesn’t remove those worries entirely, but it closes the distance that makes them harder to manage. Projects like this typically start from around £60,000 inc VAT, and how much a garden annex costs depends on size, specification and site conditions.

How do you know if a garden annex is the right option for your parent?

There’s no single answer here, and we’d rather be honest about that than pretend otherwise. An annex tends to suit families where a parent still manages day to day with a degree of independence, wants to stay close rather than move into a care setting, and doesn’t require the kind of round-the-clock medical support that only a staffed facility can provide.

It’s less straightforward where a parent needs regular nursing care, has complex medical needs, or would be genuinely isolated living semi-independently even with family nearby. An annex puts a parent closer to family, not next to a care team, and it’s worth thinking honestly about which one your situation actually calls for. Some families find an annex is the right fit for now, with care needs reassessed as things change. Others decide a care setting makes more sense from the outset. Neither is the wrong answer, and this isn’t a decision to make on cost alone.

How do you design a garden annex for changing needs?

One of the most useful things about building an annex from scratch, rather than adapting an existing space, is that accessibility can be designed in from day one rather than bolted on later. Wider 850mm doorways, wet rooms and step-free access are all things we build in as standard, not retrofitted once a need becomes urgent. We also install the paths and ramps connecting the annex to the main house, so the whole approach works as one considered space rather than a patchwork of later fixes.

This matters because needs at 75 rarely look the same as needs at 85. A parent who’s fully mobile now may need a wet room in a few years, and building for that possibility from the outset is far simpler, and far less disruptive, than trying to retrofit a bathroom around someone who’s already living in the space. Our guide to wheelchair accessible garden annex design goes into more detail on how we approach this.

What is the real cost of a garden annex compared to a care home?

Cost is rarely the only factor in this decision, but it’s usually part of it. Care home fees typically run to £45,000–£80,000 or more a year, for as long as care is needed, while a garden annex is generally a one-time cost from £60,000 inc VAT for the build itself, with groundworks confirmed separately following a site survey. Over several years, the difference in outlay can be considerable, though it’s not the whole picture: an annex also needs a garden with room to build in, and it assumes a parent’s needs fall within what family support at close proximity can reasonably cover.

We’ve written more on this in our garden annex versus care home comparison, which weighs cost alongside independence and the level of support involved, without steering families towards either option.

Do you need planning permission for a garden annex for an elderly parent?

An annex intended for permanent habitation, rather than occasional use, typically requires full planning permission rather than falling under permitted development. We offer a full planning application service on clients’ behalf, including all drawings and dealings with the local authority, for a £1,500 inc. VAT planning package. This is optional, and homeowners can manage the planning process themselves – but given the specialist nature of the work, most choose to hand it over. Our full guide to planning permission for garden annexes covers this in more depth.

If you’re at the stage of weighing this up for a parent, whether that’s in Lewes, Guildford, or somewhere further afield across the South East, the most useful next step is usually a straightforward conversation rather than a decision made from a spreadsheet. We’re happy to talk through what’s realistic for your garden, your family and your parent’s needs, honestly and without pressure. You can also read about how other families have approached this in our customer stories.

If you’d like to talk through whether a garden annex could work for your family, get in touch and we’ll help you think it through.

Frequently Asked Questions