Double Garage Conversions Manchester

A double garage conversion gives you enough space for two rooms, a self-contained annexe or a room plus storage. We plan double garage conversions across Manchester and the wider region around how your household actually lives.

Granny annexe
Half conversion with storage
Bedroom suite
Open-plan family room

Get a free quote Prices & estimator

£16,000 – £28,000

Typical 2026 guide for a double garage conversion in Greater Manchester. A double garage turned into an annexe with kitchen and shower room is usually around £28k–£40k+. Fixed, itemised quotes after a free survey. You get a fixed, itemised price after a free survey.

What you can do with a double garage conversion

A double garage is roughly twice the floor area of a single, and that changes the conversation. Instead of asking what one room you want, you can plan a layout: a bedroom with a proper ensuite, an open-plan family room, two separate rooms off a short hallway, or a self-contained annexe for a relative.

Plenty of owners choose a half conversion, turning one bay into living space and keeping the other as a garage or store. That keeps a place for bikes, tools and the lawnmower while still adding a full room to the house. Where part of the garage is kept, Building Regulations require fire separation between the two, which we build in as standard.

The extra width also helps with light and proportion. Where a single garage can feel like a corridor, a double is closer to square, so furniture can sit in the middle of the room and you can fit two windows across the front. That makes a converted double feel like part of the original house rather than an add-on.

Double garage conversion cost

Our 2026 guide for a double garage conversion in Greater Manchester is around £16,000 to £28,000. The lower end suits a single large room or a half conversion with storage retained; the upper end covers two rooms with a shower room, more windows and more complex heating and electrics.

A full annexe, with a kitchenette, shower room and its own entrance, typically costs around £28,000 to £40,000 or more. Each ensuite adds roughly £5,500 to £9,000 depending on fittings and how far the drainage has to run.

Because a double gives more choices, two quotes can look very different. Ours is fixed and itemised, so you can see exactly what each part of the layout costs and adjust before you commit. Full ranges are on our cost page.

Planning a double garage annexe

A double garage annexe is one of the most popular reasons people call us. It lets an older parent live close by with their own front door, or gives grown-up children space without leaving home. A typical layout puts a bedroom and shower room at the back and a living area with kitchenette at the front, where the light from the old door openings is best.

If the annexe is for family and stays part of your home, an attached double garage conversion is often permitted development. Creating a separate dwelling, or a garage where permitted development rights have been removed, does need planning permission, and we will tell you which applies at survey stage. See our garage conversion with ensuite page for more on bathrooms.

Building a double garage conversion properly

A wider span brings its own considerations. Double garages often have two doors with a central pier, or one long opening with a large lintel, so the new front wall needs careful detailing. Roofs vary too, from pitched tiles with useful loft space to older flat roofs that need upgrading to modern insulation standards.

Heating a larger room evenly usually means more than one radiator, and the floor area makes good insulation under the new floor especially important. These are all things we price up front, and Building Regulations sign-off is part of every job. Projects take longer than a single garage, and we give you a clear programme before work begins.

If you have a double garage attached to a neighbour's, or shared walls on either side, the Party Wall Act may apply when we cut into or build on that wall. We explain whether it affects your project at survey so there are no surprises later.