How long does an extension take?
A single-storey kitchen extension takes 8 to 14 weeks on site, after 8 to 16 weeks of design and tendering. Two storeys take 14 to 24 weeks on site. If you need planning permission, add about 12 weeks before any of that.
Every stage, from the first drawing to the kitchen going in, with the weeks for each.
Free, no obligation. One local builder prices it, not five.
- 8–16 weeksdesign, drawings and tendering
- 12 weeksplanning decision and appeal period, if needed
- 8–14 weekson site, single storey
- 14–24 weekson site, two storeys
The stages, week by week
- Design and drawings: 8 to 16 weeks with tendering. Measured survey, drawings, the engineer's design for the steel and foundations, and pricing by builders.
- Planning permission, if needed: About 12 weeks. Newspaper and site notices, then 8 weeks for the council's decision and a 4-week appeal period. Exempt extensions skip this.
- Commencement notice, if needed: 14 to 28 days before work. Needed for an extension over 45 m² or one that needed planning permission. Lodged online with the council, €30.
- Groundworks: 2 to 3 weeks. Digging out, drains moved, foundations and the floor slab with its insulation.
- Walls and roof: 3 to 4 weeks. Blockwork or timber frame, the roof structure, the steel, then the roof covering. The extension is weathertight at the end of this.
- Windows, first fix and the opening: 2 to 3 weeks. Doors, windows and rooflights in, wiring and pipes, and the old back wall knocked through.
- Plaster, floor, kitchen: 2 to 4 weeks. Plastering, the screed and floor, the kitchen fitted, second fix electrics and plumbing, decoration.
The on-site stages overlap. A typical single-storey job adds up to 8 to 14 weeks.
What makes it take longer
- Drains or a manhole under the footprint that have to be moved.
- Waiting for windows and rooflights: made to order, often 4 to 8 weeks from order.
- Changes once work has started.
- Rain during groundworks and before the roof is on.
- A planning appeal.
Plan your extension and see the cost
Nine quick taps. You see your plan build up as you go: the price range, what moves it, the planning position and the build time. Your number is only asked for at the end, if you want a real price.
A 25 m² single-storey rear extension in Ireland, mid-range, with wide glass doors and a new kitchen: €62,000 to €90,000 all in, including VAT and fees.
How this is worked out
We start from what single-storey extensions cost to build per square metre in each part of Ireland, including VAT at 13.5%, and the rates for side, wraparound, two-storey and heavily glazed extensions. Standard finishes take the lower half of the range, mid-range the upper half, and high spec or a wall of glass the glazed rate. Then we add professional fees (design, engineer, BER) and, if you want one, a new kitchen at your level of finish. Totals are rounded to the nearest €1,000. It's an estimate to plan with, never a quote: the builder prices your house after seeing it.
Questions people ask
How long does a kitchen extension take in Ireland?
A single-storey kitchen extension takes 8 to 14 weeks on site, after 8 to 16 weeks of design and tendering. Two storeys take 14 to 24 weeks on site. If you need planning permission, add about 12 weeks before any of that.
How long does planning permission take for an extension?
8 weeks for the council's decision, then a 4-week appeal period before final permission. Longer if the council asks for more information or someone appeals.
Can I stay in the house during an extension?
Usually. The old back wall comes out late, once the extension is weathertight, so you lose the kitchen for a few weeks, not the whole job.
What time of year should we start?
Spring, so groundworks and the roof happen in drier weather. But builders are booked up for spring, so get prices in winter.
Get a free quote for your extension
Plan it in under a minute, see the cost, and one vetted builder who covers your county rings you with a proper price.