How houseextension.ie works
What happens to your plan, and how the prices are worked out.
Free and no obligation. Your plan goes to one builder, not a list.
How it works
houseextension.ie prices extensions, explains the planning and building rules in plain words, and passes each plan sent to it to a single vetted builder in the visitor's county. That builder visits, prices the work in writing and, if you go ahead, builds it under an agreement between you and them. You never pay us.
What happens to your plan
It goes to one builder only, who works in your county and builds house extensions. There's no list and no ring-round. Their written price is yours to accept or turn down, and you can get other quotes as well.
Where the prices come from
The per m² rates are what one-storey, two-storey, side, wraparound and heavily glazed extensions cost to build in each region of Ireland now, VAT at 13.5% included. Fees, en-suites, kitchens and garage conversions are priced separately. When building costs move, so do the rates. Treat them as a figure to plan with: the real price comes from a builder who has seen your house.
The rules and the numbers
Planning answers follow the exempted development regulations as they stand from 27 July 2026, and building control answers the regulations that changed the same day. Bedroom counts are from Census 2022 and the prices people paid for homes are the CSO's.
Mistakes and contact
If you find a mistake on the site, email hello@houseextension.ie and it will be corrected. Questions about your data go to privacy@houseextension.ie.
Plan your house extension
Four quick taps, and your plan fills in as you answer: what it costs, whether it needs planning permission and how long it takes. Contact details come last, and only if you want a builder to price it.
25 m² single-storey rear, mid-range finish: €52,000 to €65,000, including VAT and fees.
How the estimate is worked out
Every kind of extension has a build rate per m² for each region of Ireland, VAT at 13.5% included. A standard finish uses the lower half of that range and mid-range the upper half; high spec or a wall of glass moves the build to the glazed rate. Design, engineer and BER fees go on top, with anything you tick (an en-suite, a kitchen, a steel beam into the house) priced at your finish. A garage conversion gets one price for the whole job, since the walls and roof are already standing. Totals are rounded to the nearest €1,000. Use it to plan with. It isn't a quote: a builder prices your house after seeing it.
About us
Who builds the extension?
A single vetted builder for your area. They do the pricing and the building.
Who sees my details?
Only the one builder your plan is passed to, and only after you send it and agree.
Every guide, calculator and county page
Jump straight to any specification guide, our interactive calculator, the technical glossary or your county page.
Price & Specification Guides
Calculator, FAQ & Glossary
Room to grow, without moving
Pick the type, the size and the finish to see the cost in your county. When you want a firm price, your plan goes to a single vetted builder for your area.