Guides · Garage conversion guides
Garage conversions: cost, planning permission and building regulations.
In short: Converting an integral or attached garage usually doesn't need planning permission, but building regulations approval is always needed. Cost depends mainly on the garage's existing condition, whether plumbing is needed and how the old garage door opening is filled.
How much does a garage conversion cost?
Cost depends mainly on the garage's existing condition and whether plumbing is needed — here's general guidance to help you budget.
General cost ranges
As general UK market guidance: a basic conversion (insulation, flooring, plastering and electrics only) often runs £6,000–£12,000. A mid-spec conversion including heating, new windows and a higher-quality finish typically runs £12,000–£20,000. A higher-spec conversion including plumbing for an en-suite or kitchenette can run £20,000–£35,000 or more.
These are indicative of the wider UK market and aren't East Yorkshire Renovations' confirmed pricing.
What moves the price
Existing damp and floor level issues can add cost if they need addressing before the conversion can proceed. Plumbing, if included, is usually the next biggest factor, followed by window and door replacement and the interior finish specified.
Do you need planning permission for a garage conversion?
Converting an integral garage usually doesn't need planning permission — here's the general position and where it can differ.
Integral and attached garages
Converting an integral or attached garage into living space is usually treated as an internal change of use within the existing footprint, which doesn't normally need planning permission. This can change if you're also altering the garage door opening to a full window, or changing the roofline.
Detached garages
Detached garage conversions follow similar building regulations requirements, but may be more likely to need planning permission if the intended use, height or external appearance is changing significantly.
What building regulations apply to a garage conversion?
Unlike planning permission, building regulations approval is required for a garage conversion regardless of whether planning permission is needed.
What's covered
Building regulations for a garage conversion cover structural work (particularly around the former garage door opening), insulation standards, damp-proofing, fire safety (especially important where there's a room above the garage), ventilation and electrical work.
Fire safety
Fire safety requirements are a bigger consideration for garage conversions than for many other home improvement projects, particularly where the garage sits below a bedroom or is part of an escape route, and this is assessed as part of the building regulations process.
What happens to the garage door and windows in a conversion?
The old garage door opening is one of the first things to sort out, and it shapes how the finished room looks from outside.
The garage door opening
This is typically either bricked up with matching brickwork, or replaced with a window, depending on the room's new use and how much natural light you want. Matching the new brickwork to the existing house is worth doing properly rather than leaving an obvious patch.
Additional windows
Depending on the room's use and how much natural light the existing structure allows, additional windows may be added — a bedroom conversion in particular may need a window that meets minimum size and opening requirements for fire escape.
Frequently asked questions
Garage conversions: cost, planning permission and building regulations: FAQs.
Is a detached garage conversion more expensive than an integral one?
Often, yes, since a detached garage typically needs its own services run out to it, similar to a garden room, which adds cost compared with an integral garage already close to existing supplies.
Does changing my garage door to a window need planning permission?
It can do, depending on your property and the extent of the change. We check this for your specific garage as part of the consultation.
Do I need building control sign-off even for a small conversion?
Yes, building regulations approval applies regardless of the conversion's size, since it covers structural and safety requirements rather than being size-dependent in the way some planning rules are.
Can the garage door opening be kept as a feature, like a large window?
Yes, some conversions keep a large glazed opening where the garage door was, rather than bricking it up entirely, depending on the design and how much light is wanted.
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