How much does a house extension cost in Ireland?

A single-storey rear extension typically costs €1,500–€2,500 per m². A standard 25m² extension costs €40,000–€60,000 fully finished including VAT. Two-storey extensions cost more due to structural complexity.

Do I need planning permission for a house extension in Ireland?

Extensions under 40m² to the rear of a house may qualify as exempted development, provided they meet certain conditions. Side extensions and any extension that brings the total over 40m² require full planning permission.

How long does a house extension take in Ireland?

A typical single-storey extension takes 10–16 weeks from start to finish. Planning permission (if required) adds 8–12 weeks. Two-storey extensions take 16–24 weeks.

Do I need an engineer for a house extension in Ireland?

Yes. A chartered engineer or architect is required to sign off on the structural design and issue a Certificate of Compliance. This is needed for your solicitor and mortgage lender if you sell the property.

House Extension Cost Ireland 2026 — Compare Quotes

What does a House Extension do?

Single-storey rear extensions

Two-storey and side-return extensions

Kitchen and living space expansions

Planning permission applications

Structural engineer certification

Full project management

House Extension Costs in Ireland (2026)

Typical 2026 house extension costs in Ireland:

Item	Typical cost
Single-storey extension (per sqm)	€2,200 – €3,000
Two-storey extension (per sqm)	€2,000 – €2,800
Typical 20 sqm kitchen extension	€50,000 – €70,000

Indicative 2026 ranges — exact pricing varies by county and property. Compare free quotes to see your actual costs.

Find House Extensions by County

Select your county to find local house extensions and get free quotes.

Find a House Extension in Ireland

What does a House Extension do?

House Extension Costs in Ireland (2026)

Find House Extensions by County

Frequently Asked Questions

Get Free Quotes

Regulation Body

Find a House Extension in Ireland

What does a House Extension do?

House Extension Costs in Ireland (2026)

Find House Extensions by County

Frequently Asked Questions

Get Free Quotes

Regulation Body