House Extension FAQ

EUR 20,000 is below current market cost for a habitable house extension in Ireland. Realistically you'd cover groundworks and a small shell at that price - around 8-10 sqm of unfinished structure. A fully finished single-storey extension in Dublin typically starts at EUR 50,000 for 15-20 sqm. We always quote a fully fitted, fully decorated, fixed-price number so you know exactly what you'll get.

EUR 30,000 will deliver a small structural extension shell of around 12-15 sqm, but rarely a finished, fitted-out room in Dublin. To stretch the budget, we suggest combining the extension with simpler internal renovation works rather than a high-spec finish. A free site survey gives you a real fixed-price number for your specific home.

Budget EUR 2,400 to EUR 3,200 per square metre fully fitted in Dublin. A 30 sqm rear kitchen extension typically lands at EUR 75,000 to EUR 100,000; a 40 sqm extension is EUR 100,000 to EUR 140,000. Steel frames, glass roofs and high-end kitchens push numbers higher.

Outside Dublin, expect EUR 2,200 to EUR 2,900 per square metre fully fitted - around 10-15% lower than central Dublin pricing. We work across Leinster from our Dublin 2 base, including Drogheda, Co. Louth and the wider M1 corridor.

A two-storey extension in Ireland typically costs EUR 130,000 to EUR 220,000 for 30-50 sqm of new floor area. Per-sqm rate is slightly lower than single-storey because the roof and foundations are spread over two floors.

A 20 sqm extension in Ireland is typically EUR 55,000 to EUR 75,000 turnkey, including kitchen units if it's a rear kitchen extension, flooring, decoration and electrics.

A 40 sqm extension - the largest single-storey rear extension allowed under exempted development - costs EUR 100,000 to EUR 140,000 in Ireland depending on glazing, finishes and any kitchen reconfiguration.

A typical attached-garage conversion to a habitable room in Ireland costs EUR 18,000 to EUR 35,000. That includes new floor build-up, insulation, plastering, electrics, heating extension and a window in place of the garage door.

On average around EUR 22,000 to EUR 28,000 in Dublin for a single-bay attached garage conversion - assuming the existing structure is sound and no underpinning is required.

A small 15-20 sqm rear extension in Ireland generally costs between EUR 50,000 and EUR 75,000 fully fitted. Side returns of 8-12 sqm can come in slightly cheaper at EUR 40,000-EUR 55,000.

EUR 2,400 to EUR 3,200 per square metre for a finished house extension in Ireland - so a 30 sqm extension is normally EUR 75,000 to EUR 100,000. We supply a fixed-price contract for that number.

A 30 sqm rear extension in Dublin is typically EUR 75,000 to EUR 105,000 turnkey. Glass-roof or large bi-fold designs add EUR 8,000 to EUR 15,000 to that range.

Budget EUR 2,400 to EUR 3,200 per square metre for a Dublin house extension. The total depends entirely on size and finish - we always quote a fully fitted fixed price.

EUR 2,200 to EUR 3,200 per square metre for a fully finished house extension in Ireland. Dublin sits at the upper end; rural Leinster is closer to the lower end.

For a typical 30 sqm finished single-storey rear extension on a Dublin house, expect EUR 75,000 to EUR 105,000. Smaller side-returns start at EUR 50,000.

A 20 sqm extension fully fitted in Ireland costs around EUR 55,000 to EUR 75,000. Side-return 20 sqm projects can be slightly cheaper because of simpler structure.

A typical 30-40 sqm kitchen extension in Ireland costs EUR 80,000 to EUR 130,000 turnkey, including kitchen units, flooring and decoration. Smaller side-return kitchen extensions start around EUR 55,000.

A 4 metre rear extension - typically about 25-30 sqm depending on the width of the house - costs around EUR 70,000 to EUR 95,000 fully fitted in Dublin.

Roughly EUR 2,800 to EUR 3,400 per square metre fully fitted in Dublin. A 35 sqm two-storey rear extension would land around EUR 105,000 to EUR 130,000.

Budget EUR 30,000 to EUR 45,000 for a simple Velux conversion, EUR 45,000 to EUR 65,000 for a dormer conversion with a bedroom and ensuite, and EUR 60,000 to EUR 80,000+ for a hip-to-gable conversion on a semi-detached home.

A straightforward Velux conversion that only adds roof windows is usually exempted development. A dormer or hip-to-gable conversion that changes the roof profile - or any dormer facing a public road - typically needs full planning permission. We confirm exemption in writing before quoting.

A Velux conversion keeps the existing roofline and adds roof windows for light and ventilation - the cheapest and fastest option, though headroom depends on your existing roof pitch. A dormer conversion adds a flat or pitched-roof box dormer for full standing height across the room, at extra cost.

Most Velux conversions take 6 to 8 weeks. Dormer and hip-to-gable conversions typically take 8 to 12 weeks, covering structural work, insulation, plumbing for an ensuite and full decoration.

Not quite - building regulations require at least 2.2m to 2.4m of headroom at the highest point and a compliant fixed staircase, so very low roof pitches may need a dormer or hip-to-gable extension rather than a simple Velux conversion.

A Shomera-style garden room under 25 sqm is typically exempt from planning permission in Ireland, provided it sits in the rear garden, doesn't exceed boundary heights and isn't used as habitable sleeping accommodation. We always confirm exemption in writing before quoting any garden-room project.

Most garage conversions in Ireland are exempt from planning if the garage is attached, the use stays residential and the external appearance is maintained. Detached garages or layout changes that affect the front facade may need full permission.

Up to 40 sqm to the rear under exempted development in Ireland, subject to height (4m flat / 5m pitched), boundary distances and the size of any existing extensions. We confirm exemption in writing before tools are lifted.

Up to 40 sqm to the rear of a house under exempted development - subject to height, boundary and existing-extension rules. Two-storey rear extensions are typically capped at 20 sqm under exempted development.

Most semi-detached and terraced houses can extend 40 sqm to the rear under exempted development, with a single-storey height cap of 4 metres (flat roof) or 5 metres (pitched). Two-storey rear extensions normally need full planning permission.

Most rear extensions in Dublin take 12 to 16 weeks from groundworks to handover. Smaller 15-20 sqm builds finish in 10 weeks; complex steel-frame or glass-roof extensions can run to 18 weeks.

Most house extensions we build in Dublin take 12 to 16 weeks from groundworks to handover, whatever the project type. Smaller projects can finish in 8 to 10 weeks; larger or more complex builds can run to 18 weeks or more.

A kitchen extension typically takes 12 to 16 weeks - a compact side-return finishes in around 12 weeks, while a full 40 sqm open-plan build takes closer to 16 weeks.

Including design and planning, budget 4 to 6 months for a project that qualifies as exempted development, or 6 to 9 months if full planning permission is required. Construction itself is usually 10 to 16 weeks of that total.

The statutory decision period is 8 weeks from a valid planning application, though requests for further information commonly extend that to 12 to 16 weeks in practice. We design applications to minimise the chance of a further-information request.

A full home renovation - rewiring, replumbing and layout changes - typically takes 12 to 24 weeks depending on scope. Combining a renovation with an extension usually adds 4 to 8 weeks to the extension-only timeline.

40 sqm is roughly 8m x 5m - about the size of three single-car garages side by side. It's large enough for an open-plan kitchen, dining and living space, or two full-size rooms, and is the maximum single-storey size allowed under exempted development.

20 sqm is roughly 5m x 4m - big enough for a generous kitchen extension or a single large family room, though usually too small to fit a full open-plan kitchen, dining and living space all at once.

Most homeowners need 25 to 35 sqm for a comfortable open-plan kitchen, dining and living space. Under 20 sqm usually means choosing between dining and lounging space rather than fitting both.

We provide a fully dimensioned floor plan as part of every design package, tailored to your home's actual layout and boundaries - a generic template rarely fits a real Dublin plot. Book a free site survey and we'll sketch initial options for your specific house.