A bright annexe with a white kitchenette and a shower room off it.

Garage to granny flat conversion

Someone you love close by, with a bedroom, shower room and kitchenette of their own. A garage annexe keeps family together without anyone moving house.

A garage annexe typically costs £33,500 to £54,000, VAT included. See prices

Get a quoteSee prices

Garage annexe and granny flat ideas

Their own space, a few steps from yours.

For a parent who needs a little help, a grown-up child saving for a home, or a carer who stays over. Independent enough to feel like their own, close enough to pop in.

Tell us who it is for
Kitchenette and sofa
Kitchenette and sofa
Compact kitchenette
Compact kitchenette
Walk-in shower
Walk-in shower
Bedroom
Bedroom
Bed and living space in one
Bed and living space in one
Small kitchen by the window
Small kitchen by the window
Shower room
Shower room
Sitting room
Sitting room
Kitchen and sitting area
Kitchen and sitting area
Simple kitchenette
Simple kitchenette
Shower, toilet and basin
Shower, toilet and basin
Bed and bedside table
Bed and bedside table
Bed, kitchen and sofa in one room
Bed, kitchen and sofa in one room
Black and wood kitchenette
Black and wood kitchenette
Glass shower
Glass shower
Sofa and TV
Sofa and TV
  • Kitchenette and sofaKitchenette and sofa
  • Compact kitchenetteCompact kitchenette
  • Walk-in showerWalk-in shower
  • BedroomBedroom
  • Bed and living space in oneBed and living space in one
  • Small kitchen by the windowSmall kitchen by the window
  • Shower roomShower room
  • Sitting roomSitting room
  • Kitchen and sitting areaKitchen and sitting area
  • Simple kitchenetteSimple kitchenette
  • Shower, toilet and basinShower, toilet and basin
  • Bed and bedside tableBed and bedside table
  • Bed, kitchen and sofa in one roomBed, kitchen and sofa in one room
  • Black and wood kitchenetteBlack and wood kitchenette
  • Glass showerGlass shower
  • Sofa and TVSofa and TV

Garage granny flat layouts

A double garage fits a full granny flat: a living room with a kitchenette, a bedroom and a shower room, about 30 square metres in all.

A single garage takes a bedroom with its own shower room, with meals shared in the house. Use the buttons above the plan to compare them.

Have yours measured at the visit
Example floor plan: a granny flat in a double garageA double garage about 5.4 by 5.6 metres split into a living room with a kitchen along the back wall, a table for two, and a sofa and armchair around a coffee table on a rug; a bedroom with a double bed, bedside tables and a wardrobe; and a shower room with a walk-in, level-access shower, a toilet and a basin. The door from the house opens into the living room, and both front windows are where the garage door was.Living room and kitchen2.9 × 5.6 mBedroomShower room5.4 m5.6 m
A double garage as a granny flat: living room and kitchenette, bedroom, and shower room.

How do you convert a garage into an annexe?

An annexe is a bedroom, a shower room and often a kitchenette in one, so it needs a little more than a single room. Here are the questions families ask.

A builder fitting a new window frame.

Can they get out safely in a fire?

The garage door comes out and an insulated wall goes in, with a double-glazed window. A bedroom needs a window big enough to climb out of, unless it opens onto a hallway leading outside. Mains smoke alarms go in too.

A fitter laying a new wooden floor.

Is the floor safe to walk on?

The concrete floor gets a damp-proof layer and insulation, raised to the level of the house where it can be. No step between the house and the annexe makes it easier for anyone less steady on their feet.

A builder fitting insulation.

Will they be warm, and away from the noise?

Walls and roof are insulated like the rest of the house, which keeps the annexe warm and quieter. A fire door goes between the annexe and the house where building control asks for one.

A hand turning a radiator valve.

Can it have a shower and a kitchenette?

A shower room and kitchenette need a water supply and drainage, and the distance to the drains affects the price most. The shower can be a walk-in one with no tray to step over. Both rooms get an extractor fan to take steam outside.

An electrician fitting a wall socket.

Can they run their own heating?

Sockets go where the kettle, hob and lamps will be, with heating your relative can set for themselves. New circuits are tested and certified.

An inspector checking the inside of a house.

Will it count when we sell?

Building control inspects as the work goes and issues a completion certificate at the end. Keep it with the house deeds: buyers and their solicitors will ask for it.

Garage conversion annexe rules

Councils approved 123 of the 145 decided annexe applications in council records, a little under the 92% for garage conversions as a whole. The refusals show what they look for.

It stays linked to the houseShared front door, garden and bills. Stratford-on-Avon refused a layout that could have worked as a separate home, and Birmingham refused one it judged independent of the house.

Close by and a sensible sizeAn annexe is part of your home, so it should feel like it. One was refused for being too large and 16 metres from the house to count as part of it.

Good light and room to liveWindows, outlook and space matter. Warwick refused a double garage turned into a unit for elderly relatives because of poor living conditions.

The right paperworkFamily use is one thing, a holiday let or rental is another and needs permission. Stratford-on-Avon refused holiday use of a garage because the wrong application had been made.

Council records collected by PlanIt for eight West Midlands councils, 2016 to October 2026, with the refusal letters read on each council's planning site. Applications, not finished conversions.

How much does it cost to convert a garage into a granny flat?

A garage annexe with a bedroom, shower room and kitchenette typically costs £33,500 to £54,000, VAT included. The distance to the drains and the size of the kitchen move the price most. You get it in writing after the visit.

Work out the cost of yours
Your annexeTypical cost
Granny flat: bedroom, shower room and kitchenette£33,500 to £54,000
Bedroom with its own shower room£21,000 to £32,500
Detached garage: power, water and drains from the house£1,200 to £8,500 more

Prices include VAT and were checked on 14 October 2026. Annexes start from around £30,000. A planning application, if yours needs one, is extra. Ask us for a price.

Can I get a grant for a garage annexe?

If the annexe is for someone disabled, a Disabled Facilities Grant from the council may help pay for the parts of the work they need.

Up to £30,000In England, councils give grants of up to £30,000 for changes that help a disabled person live at home.

For the work they needExamples include a downstairs bedroom, a level-access shower, wider doorways and suitable heating.

Based on incomeThe amount usually depends on household income and savings over £6,000, and it does not reduce benefits.

Source: Disabled Facilities Grants on GOV.UK. Your council assesses the need and decides what it pays for, so speak to them early.

Do you pay council tax on a garage annexe?

No, for a dependent relativeAn annexe lived in by a relative aged 65 or over, or one who is severely disabled, can be exempt.

Half, for familyA 50% discount may apply when the annexe is used by you or by a member of your family.

Its own band if self-containedA fully self-contained annexe gets its own council tax band, which is when these reductions come in.

Sources: Solihull Council discounts and exemptions and GOV.UK. Other councils use the same national rules; check yours when you apply.

Planning an annexe for someone you love? Tell us about your garage and we will price it.

Get a quote

Questions about garage annexes and granny flats

Every family is different. Tell us who the annexe is for and what they need, and we will talk it through at the visit.

Ask us a question
Can I convert a single garage into a granny flat?

Yes. A single garage takes a bedroom with its own shower room, as the plan above shows. A kitchenette as well is a squeeze, so many families keep meals in the main house. That also keeps the annexe clearly part of your home.

Do I need planning permission to convert my garage into an annex?

Not always. An extra bedroom and shower room for your own household is usually treated like any garage conversion. An annexe that could be lived in as a separate home, with its own kitchen and front door, often needs permission. The rules for outbuildings do not cover self-contained living. Councils approved 123 of the 145 decided annexe applications in council records. Check with the council before work starts. Planning Portal on outbuildings.

What is the 4 year rule for garage conversions?

It used to mean a council could not act against unauthorised building work after four years. In England, for work finished on or after 25 April 2024, the limit is now ten years. It is a defence of last resort, not a way to skip permission. Councils want proof, and certificates have been refused where owners could not show the garage had been lived in for the full time. The 2024 change on legislation.gov.uk.

Can I rent out a garage annexe or use it as a holiday let?

Letting it to someone outside the family, or as a holiday let, usually means it is no longer part of your home. Then it needs planning permission. One local council refused holiday use of a converted garage because the right application had not been made. Keeping it for family keeps things simple.

Can a garage annexe be made accessible?

Yes. The floor can be raised level with the house so there is no step. The shower can be a walk-in one with no tray, and doorways can be made wider for a wheelchair or walking frame. If the annexe is for a disabled relative, a Disabled Facilities Grant from the council may help pay for this work. Disabled Facilities Grants on GOV.UK.

How long does a garage to annexe conversion take?

Usually eight to twelve weeks on site. That is longer than a single room, because of the shower room, the kitchenette and the extra checks. We can talk through the timing for yours at the visit.

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Get a price for your garage annexe

We turn garages into granny flats and annexes across Solihull, Birmingham, Sutton Coldfield, Coventry and Warwickshire. Tell us who it is for and we will design it around them.

  • A visit to measure up and talk through who will live there.
  • A written price before anything is built.
  • Typical prices shown above, so you can plan ahead.

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