Garage conversions
Converting an attached garage into a room costs €15,000 to €25,000 at a standard finish, €20,000 to €30,000 mid-range and €30,000 to €45,000 high spec or with an en-suite. It is usually exempt from planning permission under Class 1, counting towards the 45 m² with any extensions built since 1964, and it is quicker than building, because the walls, roof and floor are already there.
Turning the garage into a bedroom, an office or a playroom: what it costs, what the rules ask, and what changes outside.
Free and no obligation. Your plan goes to one builder, not a list.
- €15,000–€25,000standard finish
- €20,000–€30,000mid-range
- €30,000–€45,000high spec or with an en-suite
- 45 m²the total it shares with other extensions
What it costs, and what for
A garage conversion is priced as a whole job, not per m², because the shell is there already. €15,000 to €25,000 covers insulating the floor, walls and roof, filling the door opening with a wall and a window, heating, wiring and plastering. €20,000 to €30,000 buys better windows, flooring and lighting. €30,000 to €45,000 is a high-end finish or a room with its own shower room.
Add an en-suite in the planner if the converted room will be a bedroom: €4,000 to €8,000 standard, €10,000 to €18,000 mid-range. Keeping it on the wall nearest the existing drains saves digging.
Planning: usually exempt
Class 1 of the exempted development regulations names it directly: the conversion for use as part of the house of any garage, store or shed attached to the rear or the side. It counts as an extension, so it shares the 45 m² limit with anything built since 1 October 1964.
Three things can take the exemption away. A condition in the planning permission your house was built under can remove it, and newer estates often have one. On a protected structure, work that would affect its character isn't exempt. And no extension is exempt if it would obstruct a public right of way or create a traffic hazard. If you aren't sure, ask the council for a section 5 declaration: for €80 it decides in writing whether your plan is exempt.
Plan your house extension
Four quick taps, and your plan fills in as you answer: what it costs, whether it needs planning permission and how long it takes. Contact details come last, and only if you want a builder to price it.
Garage conversion, mid-range finish: €20,000 to €30,000, including VAT.
How the estimate is worked out
Every kind of extension has a build rate per m² for each region of Ireland, VAT at 13.5% included. A standard finish uses the lower half of that range and mid-range the upper half; high spec or a wall of glass moves the build to the glazed rate. Design, engineer and BER fees go on top, with anything you tick (an en-suite, a kitchen, a steel beam into the house) priced at your finish. A garage conversion gets one price for the whole job, since the walls and roof are already standing. Totals are rounded to the nearest €1,000. Use it to plan with. It isn't a quote: a builder prices your house after seeing it.
What the building regulations ask
A garage becomes a habitable room, so it has to be built to the same standard as one. The floor, walls and roof are insulated to the limits for new work in TGD L 2022 (0.18 W/m²K for walls and floors, 0.16 for a pitched roof, 0.20 for a flat roof, 1.4 for new windows and doors). Garage floors are usually lower than the house, so the new floor is built up to meet it. The room needs ventilation and a safe way out, and a bedroom needs a window you can escape through.
Over 45 m², or with planning permission, a commencement notice goes to the council before work starts. Building regulations.
Bedroom, office or playroom
- A bedroom for a growing family or a parent moving in, often with a shower room in the back corner of the garage.
- An office away from the household noise, with its own door from the hall.
- A playroom or a den that keeps the sitting room clear.
- A utility in part of it, with the rest as a room.
Where the car goes is the one thing to settle first: once the garage is a room, the car stays on the drive.
Other ways to add room
Each has its own page: costs by size, the planning rules that apply and the weeks of building.
Single-storey rearOne new room behind the house at ground level: a family room, a playroom or a bedroom for a parent.
Two-storeyTwo new floors in one build: more living space downstairs and an extra bedroom over it.
Side extensionThe strip beside a semi or detached house, built on at one level or two.
WraparoundAn L round the back corner of the house, for one big room with a utility or toilet off it.
Bedroom and en-suiteOne more bedroom, downstairs or up, with a shower room of its own.Questions before you build
How much does a garage conversion cost in Ireland?
Converting an attached garage into a room costs €15,000 to €25,000 at a standard finish, €20,000 to €30,000 mid-range and €30,000 to €45,000 high spec or with an en-suite. It is usually exempt from planning permission under Class 1, counting towards the 45 m² with any extensions built since 1964, and it is quicker than building, because the walls, roof and floor are already there.
Do I need planning permission to convert my garage?
Usually not, if the garage is attached to the house at the side or back and the house's own planning permission doesn't take the right away. It counts towards the 45 m² limit.
Does a garage conversion need building regulations approval?
It has to meet the building regulations like any habitable room: insulated floor, walls and roof, ventilation, fire safety and a safe way out.
Can a converted garage be a bedroom?
Yes, built as a habitable room with insulation, ventilation and an escape window. Many have a small shower room added.
Is a garage conversion cheaper than an extension?
Yes, for the same room. A garage conversion is €15,000 to €25,000 at a standard finish, against €32,000 to €44,000 to build an 18 m² room at the back with fees.
Every guide, calculator and county page
Jump straight to any specification guide, our interactive calculator, the technical glossary or your county page.
Price & Specification Guides
Calculator, FAQ & Glossary
Room to grow, without moving
Pick the type, the size and the finish to see the cost in your county. When you want a firm price, your plan goes to a single vetted builder for your area.