Basement conversion cost in Ireland
A basement conversion costs €1,000 to €2,500 a m², or €30,000 to €100,000 for most whole basements. Tanking is €50 to €180 a m², a sump system €1,000 to €2,000, and digging a new basement €3,000 to €6,000 a m².
Free, no obligation. One local company prices it, not five.
- €1,000 to €2,500a m² to turn an existing basement into a finished room
- €50 to €180a m² to tank (waterproof) the walls and floor
- 6 to 12 weeksfor most basement conversions, start to finish
- €3,000 to €6,000a m² to dig a new basement
What it costs for your size
Two taps: the job and roughly how big the basement is. The answer comes from our price guide.
Typical range
€30,000 to €75,000
30 m² at €1,000 to €2,500 a m², the usual range to turn an existing basement into a finished room. Tanking with a membrane and a sump is often priced on top, at €3,000 to €12,000.
Send this for a real priceHow this is worked out
For a conversion or a dig-out, the floor area times our range a m² (€1,000 to €2,500 to convert, €3,000 to €6,000 to dig). For tanking, the typical price for a basement that size. It's a guide, never a quote: the company prices your basement after a look. Building work on a house is charged VAT at 13.5%. Ask whether the written price includes it.
What the quote should list
- The waterproofing system by name and type, where it goes, and the guarantee.
- The sump: the pumps, the alarm, the back-up and the service.
- Radon: a barrier and sump, or a test once it's finished.
- Insulation thickness on the walls and floor.
- Light wells, windows and the escape route, with any structural work.
- Electrics, heating, ventilation and the finish.
- The skip, protection for the rest of the house, and VAT.
- How anything found once walls are opened will be priced.
Get a price in 4 taps
Tap what you need and leave your number. It goes to one basement company that covers your county. They ring you back to arrange a look and a written price.
Related guides
- Basement conversionTurning a cellar or basement into a room: the steps and the price.
- Waterproofing and tankingSlurry tanking, membranes, sumps and what each costs.
- Digging out a basementDigging out, lowering the floor and underpinning.
- How long it takes6 to 12 weeks for most conversions, week by week.
Basement conversion and waterproofing guides & price breakdowns
Straight answers to what people ask most: itemised costs, specifications, planning or grants, and what to check before you book.
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Questions we get asked
What is the average cost of a basement conversion in Ireland?
€30,000 to €100,000 for most whole conversions, or €1,000 to €2,500 a m².
Is a basement cheaper than an extension?
Converting a basement you already have often costs less a m² than building an extension. Digging a new one costs more.
What adds most to the price?
Water coming in all year, lowering the floor, new light wells or escape windows, and a bathroom below ground.
Should I keep money aside?
Yes. Keep 10 to 15% aside for what's found once the walls and floor are opened.
Basement conversion and waterproofing across all 26 counties
Requests from all 26 counties go to one vetted local specialist who covers your county — from Dublin, Cork, Galway and Limerick to Kildare, Meath, Wicklow, Waterford and Donegal. Pick your county below for local prices, specifications and advice. Compare all areas covered →
Get a free quote for your basement
One company that covers your county rings you. Nothing is agreed until you accept a written price.