Granny Flat Cost Ireland: 2026 Fixed Prices and Planning Rules

The base granny flat cost in Ireland ranges from €69,000 for a 25 m² studio to €134,500 for a 48 m² two-bedroom unit, plus VAT at 13.5%. These fixed prices cover design, build, and full project management. Site works, utility connections, and professional fees are priced separately based on your specific garden.

How much does a granny flat cost in Ireland?

A granny flat costs between €69,000 and €134,500 plus VAT at 13.5% for the core build, depending on the size you choose. We provide four fixed-price options to give you cost certainty from the start.

Here are the fixed prices for our granny flats:

Granny Flat Size	Base Price (Excl. VAT)
25 m² Studio Flat	€69,000
33 m² 1 Bed Granny Flat	€93,900
45 m² 1-or-2 Bed Granny Flat	€126,500
48 m² 2 Bed Granny Flat	€134,500

These figures include the architectural design, the physical build of the structure, and full project management by Nua Living. They do not include site works, utility connections, or professional fees, as these elements change depending on your property.

What extra costs should I budget for?

You need to budget for site preparation, utility connections, and professional fees, as these vary for every property and are not included in the base build price.

Every garden is different. A flat, easily accessible garden requires less preparation than a sloped site with poor access. When calculating your total project budget, you must account for:

• Site works: Clearing the ground, excavating, pouring the foundations, and any final landscaping around the new building.
• Utility connections: Trenching and piping to connect the new unit to your main house's water supply, electricity grid, and sewage system. The further the unit is from the main house, the more this will cost.
• Professional fees: Payments for engineers to sign off on the works, or planning application fees if your specific build does not meet exemption criteria.

We assess these variables during a free site visit. This allows us to outline the exact requirements for your garden before you commit to the project. You can read more about how we manage this in our process guide.

Do I need to pay for planning permission?

You do not need to pay for planning permission if your build qualifies for the exemption under S.I. No. 340/2026, which allows detached garden dwellings up to 45 m² without planning approval.

This legislation comes into effect on 27 July 2026 and currently runs until 31 December 2030. To build without planning permission, your project must meet strict criteria:

• The unit must be located in the rear garden of the main home.
• You must leave at least 25 m² of private open garden space remaining.
• The granny flat must have a separate entrance.
• The owner of the property must live in the principal dwelling.

If your plans exceed 45 m²—such as our 48 m² two-bedroom unit—or if you cannot meet the garden space requirements, you will need to apply and pay for standard planning permission. You can find more details on these rules in our planning guide.

Even if your build is exempt from planning permission, Building Control, fire safety, and BER rules still apply in full. You will still need to pay professional fees to ensure the building is certified and compliant with Irish building regulations.

How does the construction method affect the price?

Building with ICF (Insulated Concrete Formwork) provides a permanent, highly energy-efficient concrete home rather than a temporary structure, giving you better long-term value and lower heating bills.

Nua Living builds using ICF construction. This method involves pouring a reinforced concrete core on site between two permanent layers of insulation. We do not use timber frames or steel frames, and our homes are not lightweight cabins delivered on a lorry.

Because of this solid concrete core and continuous insulation, our modular homes are designed to reach BER A1–A0. This performance sits well above Ireland's nZEB (nearly Zero Energy Building) minimum requirement of BER A2. While a permanent concrete build requires proper foundations and site works, it results in a durable home that costs very little to heat.

The construction process is also highly efficient. Once your foundations are ready, the on-site structural build takes just 5–10 days. Keep in mind that design, planning checks, and utility connections will add lead-time before the physical build begins.

Frequently Asked Questions

How much is a 1 bed granny flat in Ireland?

A 33 m² one-bedroom granny flat costs €93,900 plus VAT at 13.5%. A larger 45 m² one-or-two-bedroom unit costs €126,500 plus VAT at 13.5%. These prices cover design, build, and project management, but exclude site works, connections, and professional fees.

Are granny flats exempt from planning permission?

Under S.I. No. 340/2026, detached garden dwellings up to 45 m² are exempt from planning permission if located in the rear garden, leaving 25 m² of space, with a separate entrance, provided the owner lives in the main house. This applies from 27 July 2026 to 31 December 2030.

How long does it take to build a granny flat?

The on-site structural build using ICF takes 5–10 days once the foundations are ready. Design, planning checks, and utility connections will add lead-time before the physical build starts.

Are Nua Living granny flats delivered fully built?

No. We use ICF (Insulated Concrete Formwork), which means the reinforced concrete core is poured on site between permanent insulation layers. They are not timber or steel frames delivered on a lorry.

Ready to assess your garden?

The best way to understand the total cost for your specific property is to have the site assessed by a professional. We offer a free, no-obligation site visit to confirm your planning eligibility and outline the necessary site works. Check if your garden qualifies and get a fixed price.