Basement guides & reference
Every basement conversion cost guide, waterproofing comparison, planning and Building Regulations reference, FAQ and technical glossary in one place.
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
- One thirdof Ireland is a High Radon Area, mainly the south and west
All basement guides and services
- Basement conversionTurning a cellar or basement into a room: the steps and the price.
- Waterproofing and tankingSlurry tanking, membranes, sumps and what each costs.
- Damp basementsRising damp, penetrating damp, groundwater and condensation.
- Digging out a basementDigging out, lowering the floor and underpinning.
- Sump pumpsHow a sump works, what it costs, and back-up for power cuts.
- Basement conversion costOur full price guide, and a cost check for your size.
- Tanking vs cavity drain membraneType A against Type C, and which suits a wet basement.
- Planning permissionWhen it's exempt, and when the council decides.
- Building RegulationsFire escape, radon, damp, ventilation and insulation.
- Radon and basementsWhy basements test higher, and what a sump costs.
- How long it takes6 to 12 weeks for most conversions, week by week.
- Technical glossary (A–Z)Plain-English definitions of Type A/B/C waterproofing, BS 8102 grades, sump chambers and underpinning.
- All 26 counties coveredCounty-by-county radon, rainfall and period housing breakdown across Ireland.
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Related 2026 Ireland Specialist Cost & Technical Guides
Cross-referenced Irish pricing benchmarks, SEAI/Revenue grant rules, and county specifications from partner reference hubs:
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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
How much does a basement conversion cost in Ireland?
€1,000 to €2,500 a m² to turn an existing basement or cellar into a finished room, so €30,000 to €100,000 for most whole conversions. Waterproofing on its own is €50 to €180 a m². Digging a new basement is €3,000 to €6,000 a m². See the cost guide.
How long does it take?
6 to 12 weeks for most conversions. The waterproofing itself is 1 to 2 weeks, then 2 to 3 weeks of finishing. Digging out takes longer, because the underpinning goes in stages. See how long it takes.
Is there a grant for a basement conversion?
No. There's no national grant for converting or waterproofing a basement. Radon work isn't grant-aided either, but the EPA tests the house again for free after the work.
Will it make a mess of the house?
Some. Old plaster and floors come out first, so expect dust and a skip. Most waterproofing work stays inside the basement. Digging out means spoil leaving through a side passage or the house, so the company plans the route before they start.
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 →
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