On this page
- Can you build a home in your garden for a family member?
- What is the difference between an annexe and a separate dwelling?
- Which route suits parents, and which suits grown-up children?
- How do self-build and custom-build work for a family home?
- Is a home built for family exempt from CIL?
- How does VAT work on a home built for family?
- How do you design a home for an older relative?
- Where does everyone live while the new home is built?
- Step by step
- Questions
Who this suits
- Families who want an elderly parent close by but in a home of their own
- Parents helping a grown-up child into a first home without leaving the family plot
- Owners of long or wide gardens with a side drive or other workable access
- Households weighing an annexe against a separate home they could sell or let later
- Relatives pooling money to build on family land, with ownership agreed in writing
- Anyone who wants step-free, single-level living designed in from the start
Can you build a home in your garden for a family member?
Yes, in many gardens, but it will almost always need planning permission, and the first decision is what kind of home it will be. A new building with its own bedroom, bathroom and kitchen is either an annexe that stays part of your house or a separate dwelling in its own right. The council treats the two differently, and so do the tax and ownership rules.
The right answer depends on who is moving in, for how long, and what you want to happen to the building in twenty years’ time. An annexe suits a parent who will share meals and care with the main house. A separate home suits a grown-up child who wants their own front door, post and bills, or a family that may want to sell or let it one day.
We’re a new brand within the S&K Group, and this is one of our design and build services: you keep the land, and we design, get planning for and build the home with you. If you’d rather build to sell or let, our service for building a new home in your garden covers that, and our planning permission service can take a family scheme through the council on its own. If you’d rather not build at all, selling part of the garden, outright or subject to planning, is the other route.
What is the difference between an annexe and a separate dwelling?
An annexe is accommodation used as part of your main home, or ancillary to it in planning language. A separate dwelling is a home in its own right, with its own planning permission, and it can have its own title and be mortgaged, let or sold.
When a council approves an annexe it usually adds a planning condition tying its use to the main house, so it can’t be sold or let as a separate home. Lifting that later means applying to the council to vary or remove the condition, and the council will judge it much like a new house: access, privacy, garden space and parking all come back into play.
| Question | Annexe | Separate dwelling |
|---|---|---|
| Planning | Permission as accommodation linked to your house, usually with a condition tying it to the main home | Full permission for a new home, judged like any house built in a garden |
| Ownership | Stays on your title and usually can’t be sold on its own | Can be given its own title at HM Land Registry, then sold, let or mortgaged |
| Council tax | May qualify for an exemption or discount, depending on who lives there | Normally gets its own band and bill |
| CIL, where charged | A residential annexe exemption may apply if claimed before work starts | A self-build exemption may apply if claimed before work starts |
| VAT on the build | Often can’t be zero-rated if it can’t be used or sold separately | Usually zero-rated as a new dwelling; DIY refund scheme may cover materials |
| Space needed | Often expected to be smaller and closely linked to the house | Needs its own garden, parking, bins and workable access |
Which route suits parents, and which suits grown-up children?
For an elderly parent, an annexe is often the simpler fit. It sits close to the house, councils are usually more comfortable with a smaller building linked to the main home, and the help you give doesn’t depend on crossing a shared drive or a street. The trade-off is flexibility: when the annexe is no longer needed, it remains part of your house.
For a grown-up child, a separate dwelling often makes more sense. It can be put in their name, mortgaged by them and sold when their life moves on. It also has to work as a home on its own, so the plot needs room for its own garden, parking and bins, and an access the council will accept.
Some families plan for both: a home designed to work as an annexe now, on a plot laid out so that a separate dwelling could be argued for later. We can show you what that would take, but whether a condition is ever lifted is the council’s decision.
How do self-build and custom-build work for a family home?
Self-build means building, or commissioning someone to build, a home you will live in yourself. Custom-build is the version where a builder does the work but the household has the main say in the design and layout. In England, the legislation behind self-build registers doesn’t distinguish between the two, and our design and build service sits on the custom-build side: the family shapes the design with us and we build it.
In England, councils keep a self-build and custom housebuilding register for people who want serviced plots. You don’t need to be on it to build in your own garden; it exists to help councils plan for demand.
Self-build mortgages usually release money in stages as the build progresses, and lenders will want to see planning permission, a fixed quote and normally a structural warranty in place. If a family member is borrowing, involve their lender early. A lender will generally want security over a home with its own title, which an annexe tied to someone else’s house can’t offer.
Is a home built for family exempt from CIL?
Possibly, but only if the exemption is claimed in time. The Community Infrastructure Levy is a charge some councils make on new homes. There is a self-build exemption for the person who builds or commissions a home and will live in it as their main residence, and a separate exemption for a residential annexe built within the grounds of your own home.
Both must be claimed from the council before work starts on site, together with a commencement notice. Start first and the exemption is lost. For a self-build home there is more paperwork after completion, and the exemption can be withdrawn if, within three years of completion, the home is sold or let, or an annexe is let or sold separately from the house.
The self-build exemption belongs to the person who will live in the new home, which matters when you are building for a parent or child: they may need to be the one who claims it. We build the CIL timetable into the programme so that nothing starts on site before the forms are in.
How does VAT work on a home built for family?
Building a new separate dwelling is usually zero-rated when a VAT-registered builder does the work. If you buy materials yourself, HMRC’s VAT refund scheme for DIY housebuilders lets you reclaim VAT on qualifying building materials. You make one claim, on form VAT431NB, within six months of finishing the build. Professional fees, such as design and planning fees, can’t be reclaimed through the scheme.
An annexe is different. HMRC’s VAT guidance on buildings and construction gives a granny annexe that can’t be used or disposed of separately from the main house as an example of work that can’t be zero-rated, and the DIY claim form asks whether your planning permission prevents separate use. An annexe tied by condition is therefore often outside both. VAT turns on the exact wording of the permission, so take advice from a tax adviser before you choose a route.
How do you design a home for an older relative?
Design for the person as they may be in ten or fifteen years, not just as they are today. That means level or gently ramped routes from the parking space and from the main house, a bedroom and shower room on the ground floor, and space beside the bed and toilet for a carer or equipment.
Every new home must meet a basic level of access under the Building Regulations. In England there are higher optional standards, accessible and adaptable dwellings and wheelchair user dwellings, which a council can require through planning; you can also choose to design to them. If your relative has an occupational therapist, their advice on the layout is worth having before the design is fixed.
- A step-free entrance with a covered approach and good lighting
- A level-access shower, with walls strong enough for grab rails later
- Doors and hallways wide enough for a wheelchair or walking frame
- Sockets, switches and window handles at reachable heights
- A short, lit path to the main house that keeps privacy for both households
- Space set aside for a through-floor lift if the home has an upper floor
In Wales Every new home must meet a basic level of access under the Building Regulations as they apply in Wales. In England there are higher optional standards, accessible and adaptable dwellings and wheelchair user dwellings, which a council can require through planning; you can also choose to design to them. If your relative has an occupational therapist, their advice on the layout is worth having before the design is fixed.
Where does everyone live while the new home is built?
Usually in the main house, carrying on as normal, with the site fenced off from the rest of the garden. The things to agree early are access for deliveries and machines, where skips and materials go, working hours, and how the household, especially an older relative, gets in and out safely.
If the only route to the plot is your side drive, expect it to be busy for much of the build and plan parking elsewhere. Drainage, water and power connections may need trenches across the garden or drive, which we programme to keep disruption short.
A single home in a garden usually takes several months on site, depending on ground conditions, the design, services and weather. If the person moving in is living with you now, we plan the move around a realistic handover window and keep you updated as the build progresses.
Step by step
Free plot appraisal
We look at your plot, access and the planning picture from the desk, talk through who will live in the new home, and visit if it looks viable. There’s no cost and no obligation.
Annexe or separate home
We set out both routes for your plot, covering what each means for planning, ownership, council tax, CIL and VAT, so you can decide with your family and advisers before design starts.
Survey and design
A measured survey, then a design built around the person moving in: step-free routes, a ground-floor bedroom if needed and privacy for both households. You get a written quote after design and survey.
Planning and approvals
We prepare and submit the planning application and manage it with the council, which makes the decision. Before work starts, approval under the Building Regulations is in place and any CIL exemption has been claimed.
Build and handover
We build while you carry on living next door, with access, deliveries and working hours agreed up front. At handover you get the completion certificate and the paperwork you’ll need for council tax, lenders and any VAT claim.
Things to weigh up
- An annexe tied by planning condition usually can’t be sold or let separately, which limits flexibility later.
- CIL exemptions are lost if work starts before the claim is made, and can be withdrawn if the home is sold or let within three years.
- VAT savings available on a separate dwelling often don’t apply to an annexe; take advice from a tax adviser before choosing.
- A separate home needs its own garden, parking, bins and access, so it needs more land than an annexe.
- Family plans change: agree ownership, costs and what happens if circumstances change in writing, with a solicitor.
- Planning is the council’s decision, and an annexe is not a way round the rules that apply to a new house.
Questions about family home in your garden
Do I need planning permission for a granny annexe in the garden?
Usually, yes. A detached building with its own bedroom, bathroom and kitchen goes beyond the outbuilding allowances in householder permitted development, which don’t cover separate self-contained living accommodation. Most garden annexes therefore need a planning application, and the council will normally attach a condition linking the annexe to the main house. Your council can confirm the position for your property before you commit to a design.
Can my son or daughter own the new home?
If it is a separate dwelling with its own planning permission, yes. The plot can be transferred to them as a transfer of part at HM Land Registry, giving it its own title, and if your house is mortgaged your lender must agree to release the plot from its charge. Gifting or selling land within a family can have tax consequences on both sides, so take advice from a solicitor and a tax adviser first.
Will an annexe affect my council tax?
It can. A self-contained annexe may be banded on its own, but there are exemptions, and in some cases discounts, for annexes lived in by relatives, and the detail depends on the relative’s circumstances, such as age or disability, and on how the annexe is used. A separate dwelling normally gets its own band and bill. Ask your council’s council tax team about your situation before you decide.
Can we claim back VAT on a home for a family member?
On a separate new dwelling, often yes. Building work by a VAT-registered builder is usually zero-rated, and HMRC’s DIY housebuilders scheme lets you reclaim VAT on qualifying materials you buy yourself, with one claim made within six months of finishing. An annexe that can’t be used or sold separately from your house is often outside both. The answer depends on your planning permission, so take advice from a tax adviser.
What happens to the annexe when it’s no longer needed?
It stays part of your house. A condition tying it to the main home usually means it can’t be let or sold as a separate home, though your household can still use it as extra space. To change that, you would apply to the council to vary or remove the condition, and the council would judge the request on its planning merits, including access, privacy, parking and garden space, at the time.
Can I live in the main house while the new home is built?
Yes, that’s the normal arrangement. The working area is fenced off, and we agree access, deliveries, working hours and parking with you before anything starts. If an older relative lives with you during the build, we plan safe routes in and out of the house and keep the busiest work, such as groundworks and large deliveries, as predictable as we can.
How long does it take to build a family home in the garden?
There’s no single answer. Planning usually takes a few months from a valid application, and longer if the council asks for changes or extra reports. Building a single home then usually takes several months on site, depending on ground conditions, the design, services and weather. We give you a programme with the written quote once the design and survey are done.
Can the home be designed for someone with mobility needs?
Yes, and we suggest designing for future needs from the start: step-free access, a ground-floor bedroom and level-access shower, wide doors and corridors, and walls ready for grab rails. Building these in costs far less than adapting later. If your relative has an occupational therapist, their input on the layout is worth having before the design is fixed.