House and kitchen extensions in Dublin

What an extension costs per m² in Dublin

Onlinetradesmen.ie 2026 rates include labour, materials and VAT at 13.5% and leave out fees, planning, site preparation and the kitchen. Dublin and the commuter counties sit 15 to 20% above the national average, it says. Also Aloco Kitchens and Onlinetradesmen.ie.

A 20 m² kitchen extension, worked through

Our arithmetic on the published Dublin figures, for a 20 m² single-storey extension at the back with a made-to-measure kitchen in it:

That sits inside Aloco Kitchens' €50,000 to €90,000 for a whole open-plan kitchen extension project in Dublin. Opening the old kitchen into the new space often needs a steel beam, which Aloco puts at €2,000 to €4,000.

Do you need planning permission for a kitchen extension in Dublin?

Not if the extension fits Class 1 of the exempted development rules, as amended from 27 July 2026 (Dublin City Council; South Dublin County Council). Dublin City, Fingal, South Dublin and Dún Laoghaire-Rathdown all apply the same national regulations. The conditions:

• It's at the rear of the house and adds no more than 45 m². It was 40 m² before 27 July 2026.
• Earlier extensions built after 1 October 1964 count towards the 45 m², including ones that got planning permission.
• Any part above the ground floor is no more than 12 m² on a terraced or semi-detached house, or 20 m² on a detached house, and at least 2 metres from any party boundary.
• The walls are no higher than the rear wall of the house, and the roof no higher than the eaves or parapet for a flat roof, or the highest part of the house roof otherwise.
• At least 25 m² of private open space is left within the grounds of the house.
• Ground-floor windows are at least 1 metre from the boundary they face, and windows above the ground floor at least 8 metres.
• The roof of the extension isn't used as a balcony or terrace, and the exemption is used only on the main house.

Further restrictions are set out in Article 9 of the regulations, and the Building Regulations still apply (Dublin City Council). If your house is a protected structure, you can ask the council for a section 57 declaration on which works would be exempt (Dublin City Council).

If you do need permission

The application fee for a domestic extension is €34 (South Dublin County Council). The decision usually takes 8 weeks, and anyone can appeal within 4 weeks of it (Dublin City Council).

How long a kitchen extension takes

Allow 8 to 16 weeks for design, tendering and any planning, then 8 to 14 weeks to build a single-storey rear extension (Onlinetradesmen.ie). Order the kitchen while the building is going up: The Home Upgrade Co. fits about 12 weeks after the design is signed off, and only once the building work is finished (The Home Upgrade Co.).

Which Dublin homes have the room

The 25 m² of open space you must keep is what stops many smaller Dublin gardens. In Dublin 12 only 8% of homes have four or more bedrooms, and 81% were built from 1919 to 1970 (Dublin 12). In Malahide and Portmarnock 52% have four or more (Malahide). Measure the garden before you plan the size.

Questions people ask