How Much Does an Attic Conversion Cost in Ireland?
An attic conversion is one of the most cost-effective ways to add living space to your home in Ireland — far cheaper per square metre than an extension. Here's a realistic breakdown for 2026.
These figures are researched Irish market estimates for budgeting. Costs vary by project scope, materials and county; get at least three written quotes before starting work.
Typical builder - attic conversions costs
- Basic attic room (Velux, no dormer): €20,000–€35,000 — Staircase, insulation, boarding, electrics
- Dormer attic conversion: €35,000–€55,000 — Rear dormer, full room with en-suite
- Hip-to-gable conversion: €40,000–€65,000 — Structural, mostly for detached houses
- Mansard conversion: €60,000–€90,000+ — Full roof alteration, maximum space
- En-suite addition to attic: €6,000–€12,000 — Plumbing, tiling, sanitary ware
What affects the cost?
- Existing attic height — minimum 2.2m at ridge is needed for a habitable room
- Type of conversion — Velux only vs dormer vs full structural alteration
- Roof structure — cut rafter roofs are more suitable than trussed roofs
- Whether planning permission is required
- Quality of finish — basic vs full bedroom with en-suite
- Structural engineer and architect fees
Tips before hiring
- Get a structural engineer to assess your attic before getting builder quotes
- Check minimum head height at the ridge — 2.2m is the standard requirement
- Planning permission is required for most dormers in Ireland
- Factor in the cost of a new staircase — this can be €3,000–€8,000 alone
Frequently asked questions
- Do I need planning permission for an attic conversion in Ireland? A basic attic conversion with Velux windows that does not alter the external appearance of the roof may be exempt from planning permission. However, any dormer windows or alterations to the roof slope typically require planning permission. Always check with your local council.
- How long does an attic conversion take in Ireland? A standard Velux attic conversion typically takes 4–8 weeks. A dormer conversion with en-suite takes 8–14 weeks depending on complexity.
- Does an attic conversion add value to a house in Ireland? Yes — an attic conversion typically adds 10–20% to the value of a property in Ireland. A well-executed conversion that creates a bedroom with en-suite is particularly valuable in the current market.