Double garage conversion
A big family room, two separate rooms, or one room with the garage kept alongside. A double garage gives you around 30 square metres to play with.
Double garage conversion ideas
A double gives you choices a single cannot. One big room, two smaller ones, or half converted and the rest kept for the car.
Double garage conversion floor plans
Most double garages are about 30 to 36 square metres inside, roughly twice a single. The plans show one garage three ways, drawn to scale at the smaller end.
Two rooms suit a bedroom and an office, or two bedrooms. Half and half suits anyone who still wants somewhere for the car, the bikes or the tools.
Have yours measured at the visit
Double garage door conversion
Most people take out the garage door, whether it is one wide door or two. In its place goes a wall with two windows, so the front looks like part of the house. Others add a front door, or fit bi-fold doors, which typically add £2,500 to £5,000. Converting half? That side keeps a garage door and carries on as a garage.
The front matters more than the room behind it. When West Midlands councils have turned a conversion itself down, it was often over how the new front looked. A bay window or a porch out of keeping with the street are two examples. Brick and windows that match the house avoid that.
Source: refusal letters from Solihull, Birmingham, Coventry, Warwick, Stratford-on-Avon and Bromsgrove, Redditch councils, found through council records collected by PlanIt, 2016 to October 2026.
How much does a double garage conversion cost?
Most double garage conversions cost £25,000 to £42,000, whether you make one room or two. What moves the price most is plumbing for a shower room or kitchenette, and whether you knock through into the house. Your price comes in writing after we visit.
Use the cost calculator| In a double garage | Typical cost |
|---|---|
| One large room, or two rooms | £25,000 to £42,000 |
| Annexe: bedroom, shower room, kitchenette | £33,500 to £54,000 |
| Half converted, half kept as a garage | £14,500 to £23,000 |
| En-suite shower room | £6,500 to £9,500 more |
| An extra window | £400 to £700 more |
| Opening into the house (steel beam) | £4,000 to £9,000 more |
Prices include VAT and were checked on 14 October 2026. Half a double is priced like a single garage conversion. Something else in mind? Ask us for a price.
Other garages: single, detached, integral, half or partial and garage loft conversions.
Planning and building regulations for a double garage
Planning permission: rarely needed
46 of 50approved when people appliedConverting the inside of a double garage is normally allowed without an application. When homeowners did apply, councils approved 46 of the 50 applications that said they were converting a double garage, from 2016 to October 2026.
Building regulations: almost always needed
£835Turning a double garage into rooms needs building regulations approval. £835 is Solihull Council's fee for a double, against £570 for a single. Our prices include it, with the inspections and the completion certificate.
Planning figures: council records gathered by PlanIt for eight West Midlands councils. Many applications do not say the garage is a double, so this is a sample, and most conversions need no application at all. Fee: Solihull Council fee list, 2026 to 2027.
Questions about double garage conversions
Is your garage not quite like these? Tell us what is different and we will look at it when we come round.
Ask us a questionCan I convert a double garage into two bedrooms?
Yes. A wall splits it into two rooms of about 2.6 by 5.6 metres in a typical double, and each takes a double bed. Splitting the old door opening between the two rooms usually gives each bedroom its own window. That matters, because a bedroom needs a window big enough to climb out of unless it opens onto a hallway leading outside.
Can I convert half a double garage?
Yes, and plenty of people do. In a sample of 50 local applications to convert a double garage, nearly one in five converted half and kept the rest as a garage. A fire-resisting wall goes between the two sides. The converted half is priced like a single garage conversion, typically £14,500 to £23,000.
Can I turn a double garage into an annexe or granny flat?
Yes. A double has room for a bedroom, a shower room and a small kitchen, so it suits a parent or a grown-up child. If it stays part of your home, sharing the entrance, garden and bills, it is a garage conversion. If it could be lived in as a separate home, it needs planning permission first. An annexe typically costs £33,500 to £54,000. Garage granny flats and annexes.
How long does a double garage conversion take?
Usually three to nine weeks on site. One open room is quicker; two rooms, a shower room or a kitchenette take longer. We can talk through the timing for yours at the visit.
Can a double garage open into the house?
Yes, if it is built onto the house. Opening up the wall between them needs a steel beam, which typically adds £4,000 to £9,000. It is how a double garage becomes part of a bigger kitchen or an open-plan family room.
Get a price for your double garage
Tell us roughly what you have in mind: one room, two, or half. We will come out, measure up and talk through the options. We work across Solihull, Birmingham, Coventry and the rest of the West Midlands.
- A visit to measure the garage and hear your plans.
- A written price, agreed before work begins.
- Prices for every layout listed above.