01
Plan your conversion
Room ideas, planning guidance and a clearer brief.
Conversion type
Double garage conversion
A double garage conversion offers enough width for a generous family room, two uses or a more flexible long-term layout.
01 Professional builder introductions02 Clear cost guidance03 Planning & building control
Practical guidance for UK homeowners02
Get clear pricing
A guide range before you request quotations.
03
Build with confidence
Know what to ask about scope, approvals and warranty.
Start with the use
Use the extra width intelligently
Double garage conversions attract searches for open-plan living rooms, home gyms, offices, playrooms and annexes because the extra floor area can support more than one use. The key decision is whether to create one generous room or divide the space into rooms that each have enough daylight, heating and circulation.
- Create a large family room, cinema, gym, office or play space with room for proper furniture.
- Split the footprint into an office and utility, bedroom and shower room, or living space and storage.
- A larger opening can improve the connection to the garden but may need structural design and careful planning.
- Design heating, lighting and ventilation as a complete system across the larger volume.
Get a useful starting point
Know the room before you price it.
Use the calculator to test the floor area and finish, then request a written scope from a specialist who has inspected the property.
Estimate this projectRoom ideas
See all room ideas →Double garage conversion ideas for a larger footprint
The extra area is valuable only when the plan gives each activity enough space, light and privacy.
Explore
Living room
Create a comfortable second sitting room with a clear connection to the rest of the house.
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Cinema room
Acoustic treatment, power and ventilation matter more than simply adding a large screen.
Read moreOne room or several?
Choose the layout before the finishes
A double garage can feel like a blank canvas, but long uninterrupted walls, multiple doors and the position of the existing garage opening can make furniture planning surprisingly important. Draw the main routes through the room, decide where services will run and test whether a partition improves the space or simply creates dark leftover areas.
- Check the span, roof structure and any load-bearing wall before removing or widening openings.
- Plan zoning for quieter and noisier uses, especially if a gym or cinema shares the room.
- Use glazing, borrowed light or carefully positioned internal doors if a divided plan needs more daylight.
- Allow for a larger heating load, more electrical points and extra flooring and finishes.
Cost guidance
What does a double garage conversion cost?
A typical 6m × 6m double garage is about 36m². Using the calculator’s standard finish guide gives roughly £30,500–£41,500. An enhanced finish is around £36,000–£47,000 before project-specific extras. Plumbing or drainage may add £3,000–£5,000, and a straightforward internal partition adds about £1,000.
- Measure both bays and record any changes in floor level between them.
- Check whether the quote includes structural steel, larger windows or a new external opening.
- Compare the cost of finishing the full area with creating a smaller room and retaining storage.
Planning and approvals
Approval questions for a double garage
The larger opening and greater change to the frontage are often the first approval questions. If the conversion creates a bedroom, bathroom or annexe-style space, ventilation, fire separation, drainage and escape arrangements need to be included in the design conversation.
- Is the existing garage subject to a condition that restricts conversion or parking loss?
- Will the new opening, roof work or external appearance need planning input?
- How will the contractor demonstrate compliance across the larger floor area?
Before you request a quote
Compare double-garage quotes on scope
For a double garage, a headline total can hide large differences in what is being finished. Ask each specialist to show the area included, the number of rooms, structural openings, heating, electrics, drainage, decoration and any retained storage or parking area.
Include these details
- Whether the quote finishes the full 36m² or only part of it
- How rooms are divided and where the services run
- Structural steel, glazing, doors and roof changes
- The programme, payment stages, exclusions and completion paperwork
Questions homeowners ask
Double garage conversion FAQs
Answers to the practical questions that often shape the first design and quotation conversation.
Can a double garage be split into two rooms?
Often, yes. The plan should test daylight, heating, ventilation, circulation, fire separation and the position of doors before a partition is fixed.
Is a double garage conversion much more expensive?
It usually costs more because there is roughly twice the floor area and more finishes, heating and electrics. The calculator guide uses 36m² as a typical starting point, but the specification still matters.
Can I keep part of a double garage for storage?
Yes. A partial conversion can preserve a bay for bikes, tools or parking, but the division needs to deal with insulation, damp, fire separation and a practical access route.
Does a wider opening need structural work?
It may. Removing a garage door or creating larger glazing can affect the supporting wall and should be assessed by a competent designer or structural professional.
Relevant next steps
Plan your double garage conversion
Use the route that matches the decision you are making now.