Cost guides · 4 min read
How much does a garage conversion cost?
Converting an integral or attached garage is one of the most cost-effective ways to add a proper room, because the structure and roof already exist. Here is what to budget in 2026 for our area.
Typical garage conversion costs
| Type | Indicative cost (2026) |
|---|---|
| Single garage, simple conversion | £10,000 to £15,000 |
| Single garage, higher spec (en-suite, kitchenette) | £15,000 to £22,000 |
| Double garage conversion | £18,000 to £30,000 |
| Garage to annexe (self-contained) | £25,000+ |
What drives the price
- Whether the existing floor and foundations need upgrading for habitable use.
- Insulation to current building regulations for walls, floor and roof.
- Infilling the garage door with a wall, window or French doors.
- Adding heating, electrics, and any plumbing for a WC or kitchenette.
- Finish level and whether you knock through into the house.
Does it add value and need permission?
A well-finished conversion usually adds more than it costs, especially where off-street parking is not scarce. Most conversions are permitted development if the footprint is unchanged, but building regulations approval is required. We handle both. For a figure tailored to your garage, our instant estimator takes about a minute.
Frequently asked questions
Is a garage conversion cheaper than an extension?+
Almost always, because the walls, roof and slab already exist. You are mainly paying to make the space warm, dry and habitable.
Do garage conversions need building regulations?+
Yes. Even when planning permission is not needed, building regulations approval is required for insulation, structure, fire safety and ventilation. We manage it.
How long does a garage conversion take?+
A straightforward single garage is often just three to five weeks on site.