If you have searched for what a garage conversion costs, you have probably seen figures from about £7,500 up to £35,000 and come away none the wiser. The gap is that wide because most national cost guides are averaging a bare utility room in one part of the country against a fully finished annexe in another.
This guide gives you the real numbers we work to across Nuneaton, Bedworth, Hinckley, Coventry and the wider Warwickshire area in 2026, what sits inside each figure, and the costs that catch people out. Every price below includes VAT, because that is what actually leaves your bank account.
Garage conversion cost at a glance (Nuneaton & Warwickshire, 2026)
| Conversion type | Typical cost (inc VAT) | Timeline |
|---|---|---|
| Utility or boot room | £14,000 to £18,000 | 3 to 4 weeks |
| Single garage, basic conversion | £18,000 to £24,000 | 4 to 6 weeks |
| Single garage, high specification (en-suite, kitchenette) | £24,000 to £32,000 | 5 to 7 weeks |
| Double garage, full conversion | £28,000 to £42,000 | 6 to 9 weeks |
| Garage to self-contained annexe | £35,000 to £55,000 | 8 to 12 weeks |
Every project is individually costed with a full Quantity Surveyor breakdown before you commit, so treat these as a realistic planning range rather than a fixed price.
Why these figures sit above the national averages
You will find guides quoting £12,000 for a single garage conversion. That is not a fictional number, but it usually describes something different from what we build. The difference is normally one or more of the following.
- VAT. Many published figures are quoted excluding VAT. At 20%, a £15,000 trade figure is £18,000 on your statement.
- Building Control. A compliant conversion needs approval for insulation, fire safety, ventilation and electrics. Fees run roughly £300 to £700 and the work to actually meet the standard costs considerably more than the fee.
- The floor. Most garage floors sit lower than the house and have no damp proof membrane. Raising, insulating and tanking the floor properly adds £1,000 to £3,000. Skipping it is the single most common cause of a conversion that goes damp two winters later.
- Project management. The cheapest figures assume you are coordinating the trades yourself. Ours assume we run the job, deal with Building Control and hand you a finished room.
A cheaper number is not automatically a worse deal. But if one price is thousands below the others, the honest question to ask is which of the four items above has been left out.
Where the money actually goes
On a typical single garage conversion, the spend breaks down roughly as follows.
- Infill wall and new window or door, replacing the up-and-over door with an insulated, weather-tight wall built to match the existing brickwork.
- Floor build-up, raising the slab to the level of the house, with a damp proof membrane and insulation beneath.
- Walls, ceiling and insulation, meeting Part L thermal standards, usually £2,000 to £4,000 of the total on its own.
- Electrics and heating, new circuits, sockets, lighting and extending the heating system into the new room.
- Plastering, flooring and decoration, the finish that turns a shell into a room you want to be in.
- Building Control, inspections at each key stage and the completion certificate you will need when you sell.
Adding plumbing pushes the figure up meaningfully. A cloakroom typically adds £3,000 to £5,000 and a full shower room £6,000 to £9,000, largely because of the drainage run rather than the fittings.
What adds the most to a garage conversion cost
Drainage distance
If you want a WC or shower and the nearest soil stack is on the far side of the house, the cost of getting waste to it can exceed the cost of the bathroom itself. Worth establishing early, because it sometimes changes what the room is best used for.
Structural condition
Older garages, particularly detached ones built in the 1960s and 1970s, sometimes have shallow foundations, a single skin wall or a roof that needs replacing outright. None of this is unusual and none of it is a reason not to proceed, but it does need finding before you set a budget rather than after.
Detached versus integral
An integral garage, already sitting under the main roof and inside the thermal envelope, is the cheapest to convert. A detached garage is the most expensive, because it needs its own heating, its own services run underground from the house, and a far higher standard of insulation and weatherproofing.
Specification
The gap between a plastered room with a radiator and a room with underfloor heating, bespoke joinery and a wet room is easily £10,000 on the same footprint. This is the variable you have the most control over.
Do you need planning permission?
In most cases, no. Converting a garage into living space within the existing structure normally falls under permitted development, provided the work is internal and you are not extending the footprint or altering the roofline.
There are exceptions worth checking before you commit to anything. Some newer estates around Nuneaton and Bedworth carry planning conditions requiring the garage to be retained for parking. Conservation areas, listed buildings and properties where permitted development rights have been removed all need a formal application. Converting to a self-contained annexe with its own kitchen and entrance is usually treated as creating a separate dwelling and will need permission.
Building Regulations approval is required in every case, whether or not planning permission is. For more detail, see our guide to planning permission for garage conversions in Warwickshire.
Does a garage conversion add value?
Usually, yes, though the honest answer is that it depends on what you give up. Converting a garage typically returns a good proportion of the build cost in added value, and it is one of the cheapest ways to add a genuine room to a house, at roughly a third of the cost per square metre of a new extension.
The caveat is parking. On a street where off-road parking is scarce and most houses still have a garage, removing yours can work against you at resale. Where the garage is too narrow for a modern car and is currently storing bicycles and a freezer, which describes a great many garages in this area, converting it is close to free space.
We cover the trade-off in more detail in will a garage conversion add value to my home.
How to compare costings properly
When you are weighing up builders, the figure at the bottom matters far less than what sits above it. Check that each costing explicitly covers the floor build-up and damp proofing, insulation to current Part L standards, Building Control fees and inspections, electrical certification, making good and decoration, and removal of waste. If two numbers are thousands apart, the difference is almost always in that list rather than in anyone being greedy.
Ask for a stage payment schedule as well. Paying as work is completed, rather than a large sum up front, protects you and is a reasonable thing for any established builder to offer.
Getting an accurate figure for your garage
The ranges above will get you to a realistic budget, but no guide can tell you what your specific garage will cost, because the floor level, the drainage run and the condition of the structure are the three biggest variables and all three need looking at in person.
We will come out, look at the garage, tell you honestly what is involved and give you a full Quantity Surveyor cost breakdown so you can see exactly where the money goes. There is no charge and no obligation.
Call 024 7518 5349 or book a free consultation. We work across Nuneaton, Bedworth, Hinckley, Coventry, Atherstone, Rugby and the wider Warwickshire and Leicestershire area. You can also see recent work on our garage conversions page and in our projects.
