TL;DR — What does an attic conversion cost in Ireland?
Most Irish homeowners pay between €18,000 and €55,000 in 2026.
A basic Velux conversion on a semi-D starts around €18,000–€28,000. A full rear dormer runs €28,000–€45,000. Add an en-suite and budget €8,000–€15,000 on top of either figure.
Use the calculator at the top of this page to get a figure for your house, your county and your conversion type. It takes about 60 seconds.
Does my attic qualify?
Two things to check before anything else.
Head height — Irish building regulations require at least 2.4m of ceiling height over 50% of the floor area for a habitable room. Stand in the middle of your attic. If you can stand upright comfortably, you are close to that mark. If you are crouching, you likely need a dormer to gain enough height.
An attic that falls short can still be converted as a non-habitable space — a storage room or occasional study. But you cannot legally call it a bedroom.
Cut roof or truss roof?
Open your attic hatch and look up.
If you see a web of diagonal wooden braces filling the space, you have a truss roof — common in homes built after 1980. The webbing must be removed and replaced with steel beams. This adds €5,000–€15,000 to the total.
If you see open space with a ridge beam and rafters, you have a cut roof — common in homes built before 1980. These are straightforward to convert without major structural changes.
2026 prices by conversion type
| Conversion type | Typical cost | Planning needed? |
|---|---|---|
| Velux (rooflight only) | €18,000–€28,000 | Usually no |
| Rear dormer | €28,000–€45,000 | Usually no (rear) |
| Side dormer | €30,000–€48,000 | Check local rules |
| Hip-to-gable | €35,000–€55,000 | Usually yes |
| Hip-to-gable with dormer | €45,000–€65,000+ | Yes |
Add €8,000–€15,000 for an en-suite bathroom. Dublin prices run 15–20% above these figures — choose Dublin in the calculator to apply the uplift.
What happens next?
The calculator gives you a starting range. For the full picture — what is included, what is not, the spray foam warning, the legal steps before work starts and how to get a fair quote — read our complete guide.
Planning estimate based on April 2026 rates. Always get three written quotes before committing.
All prices are planning estimates based on April 2026 contractor rates. Always get three written quotes from a contractor registered with the CIF or CIRI before committing to any attic conversion work.
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