How Much Does a Home Extension Cost in Ireland in 2026?

By Pádraig Ryan | 5 February 2026 | 6 min read

"How much will it cost?" is the first question every homeowner asks when they start thinking about an extension. The honest answer is that it depends on many factors, but in this guide we will give you realistic figures based on what we are seeing across Tipperary and the wider Irish market in 2026. These are real-world costs, not outdated estimates from five years ago.

Average Cost Per Square Metre

As a general rule, you should budget between EUR 2,200 and EUR 3,500 per square metre for a standard home extension in Ireland in 2026. This is a turnkey figure that includes all labour, materials, VAT at 13.5%, and a standard finish. Higher specifications — underfloor heating, large-format porcelain tiles, bespoke joinery — will push you towards the upper end or beyond.

These figures have increased significantly over the past few years due to rising material costs, labour shortages, and enhanced building regulation requirements. A project that cost EUR 60,000 in 2020 could easily cost EUR 85,000 to EUR 95,000 today for the same scope of work.

Cost by Extension Type

A single-storey rear extension of around 20 to 30 square metres is the most common project we undertake. Expect to pay between EUR 50,000 and EUR 95,000 depending on size and specification. This typically includes a new open-plan kitchen-dining area, new flooring, lighting, and connection to existing services.

A two-storey extension adds a bedroom or bathroom above the ground floor space. Costs range from EUR 80,000 to EUR 150,000, though the cost per square metre is often lower than a single-storey because you are sharing the same foundations and roof structure across two floors.

Sunroom or garden room extensions are generally more affordable at EUR 25,000 to EUR 55,000, depending on the glazing system and whether the room is fully heated and insulated to building regulation standards. Be wary of extremely low quotes for sunrooms — they often indicate non-compliant builds that will cause problems when you come to sell the property.

Hidden Costs Most Homeowners Miss

The building cost is only part of the total spend. Many homeowners are surprised by the additional costs involved. Professional fees for an architect or architectural technician typically run between EUR 3,000 and EUR 8,000 depending on the project complexity. A structural engineer will cost EUR 1,500 to EUR 3,500. If you need planning permission, the application fee, newspaper notice, and site notice add another EUR 500 to EUR 1,000.

Under BC(A)R (Building Control Amendment Regulations), you will need an assigned certifier if your project is not opted out. This costs EUR 3,000 to EUR 6,000. Even with an opt-out, you still need a Commencement Notice and compliance documentation. Utility connections, temporary accommodation during construction, landscaping to repair the garden, and new furniture for the extended space all add up quickly.

How to Get an Accurate Quote

The most reliable way to understand your specific costs is to get a detailed, written quote from an experienced builder. Be cautious of quotes given over the phone or after a five-minute visit — a proper quote requires detailed drawings, a clear specification, and a thorough site assessment.

At Greenfield Build & Renovate, we provide fully itemised written quotes that break down every element of the project. There are no hidden extras — if something is not in the quote, it is not in the price. We also provide a realistic timeline so you know exactly how long the work will take. Getting three quotes is sensible, but always compare like with like. The cheapest quote is rarely the best value.

Financing Your Extension

Many homeowners in Clonmel finance extensions through savings, a home improvement loan, or by re-mortgaging. Some credit unions in Tipperary offer competitive rates for home improvements. It is worth noting that a well-executed extension typically adds more value to your home than it costs to build — a good extension can add 10% to 20% to your property value.