- Planning authority
- Cardiff Council
- Postcodes
- CF5, CF10, CF11, CF14, CF23
- Noon sun, 21 March
- About 39°
- Shadow from a 5 m eaves line
- About 6.3 m
- Planning plan
- LDP
- County
- South Glamorgan
The local picture in Cardiff
How the two households will live together shapes the planning case as much as the drawings do. If your parent will eat with you, share the garden and rely on you day to day, an annexe is the natural fit, and that is what Cardiff Council will expect the application to describe. If your son or daughter will run their own home, pay their own bills and perhaps sell up one day, it is a separate dwelling and will be assessed against the council’s Local Development Plan (LDP) as a new house. For a family in CF5, CF10, CF11 and CF14, we help set that out clearly from the start.
From first call to decision
Getting started in Cardiff costs nothing. Send us a few photos of your garden and the way in, or simply call, and we’ll look at the plot from the desk and talk through your family’s plans. If there’s a realistic scheme, we arrange a site visit. Survey and design are quoted in writing before you commit, and the build price follows once the design is settled.
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.
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 as they apply in Wales 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.
Worth checking early
- Planning is the council’s decision, and an annexe is not a way round the rules that apply to a new house.
- An annexe tied by planning condition usually can’t be sold or let separately, which limits flexibility later.
- VAT savings available on a separate dwelling often don’t apply to an annexe; take advice from a tax adviser before choosing.
Questions about garden plots in Cardiff
Can I reclaim VAT on a family annexe in Cardiff?
Often not. HMRC’s guidance gives an annexe that can’t be used or sold separately from the main house as an example of work that can’t be zero-rated, and the DIY housebuilders refund scheme asks the same question. A separate dwelling is usually treated differently. Take advice from a tax adviser before you settle the planning route, because the wording of the permission matters.
Do I need planning permission for a granny annexe in Cardiff?
Yes, almost always for a detached annexe with its own kitchen, bathroom and bedroom. Cardiff Council will treat it as accommodation linked to your home and will usually add a condition so it can’t be let or sold separately. A garden building used only as a home office or gym is a different matter, but sleeping and cooking take it beyond those allowances.
Who owns an annexe built in my Cardiff garden?
You do. An annexe stays on the title of your house and usually carries a planning condition tying it to the main home, so it can’t be transferred to the relative living in it. If a family member is paying towards it, record what they’ve put in and what happens on a sale in a written agreement drawn up by a solicitor.
How long will building work disrupt my home in Cardiff?
A single garden home usually takes several months on site, with the noisiest work, such as groundworks, drainage and heavy deliveries, concentrated near the start. We agree working hours, access and parking with you up front, and with the people next door where it affects them, so your household knows what each week will look like.
Other options in Cardiff
- Garage courts and yards
- Sell subject to planning
- Large rear gardens
- Combine gardens with your neighbours
- Joint venture on your garden plot
- Corner and side plots

