Paying for a house extension
Ireland has no general grant for building a house extension. Families pay for one from savings, by topping up the mortgage, or with a home improvement loan, and often a mix of the three. The exception is the Housing Adaptation Grant for People with a Disability: up to €40,000 from your council towards work such as a ground-floor bedroom or bathroom.
Grants, mortgage top-ups and loans: what is on offer for a bigger house, and how to fix the budget before you borrow.
Free and no obligation. Your plan goes to one builder, not a list.
- €40,000the most the adaptation grant pays towards an extension
- 100%of approved costs paid, household income up to €37,500
- 12–15%contingency to include in the loan
- €0general grant for new floor space
What grants there are
The Housing Adaptation Grant. Your council pays it, for work that makes a house suit someone with a disability, and that work can be an extension, typically a ground-floor bedroom or bathroom. The most it pays is €40,000. It covers up to 100% of the approved cost where gross household income is €37,500 or less, falling to 30% for incomes from €62,501 to €75,000. Approval has to come before any work begins. The grant on gov.ie.
SEAI grants are for improving the energy performance of the existing house: insulation, a heat pump, solar panels. They don't pay for new floor area. An extension is a natural time to do some of that work, but each grant is an application of its own, on its own terms.
Tax relief. There isn't any now. The Home Renovation Incentive ended in 2018.
Borrowing for it
- Top up the mortgage. The lender revalues the house and advances more against it, usually at a lower rate than a personal loan and over the years left on the mortgage.
- A home improvement loan from a bank or a credit union runs over fewer years, usually at a higher rate than mortgage money.
- Savings cost no interest. Whatever else you use, keep the contingency in cash.
Expect the lender to ask for the drawings and a builder's written price before approving the money. Include the 12% to 15% contingency in what you borrow: finding money mid-build, with the roof on and the old walls open, is much harder than borrowing it at the start.
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.
Paying the builder
Pay in stages as the work goes up, not up front. Agree the stages in writing before work starts, tie each one to something you can see finished, such as the foundations, the roof or the plastering, and hold the final payment until the snag list is done.
Setting the budget
- Price your plan in the planner and use the top figure.
- Add 12% to 15% for what turns up once the old walls are open.
- Add what no builder prices: furniture, curtains and blinds, appliances, and putting the garden back.
- Borrow against a builder's written price for the finished drawings, not against the estimate.
Then compare it with what a move would cost: extend or move house has the figures for each county.
Questions before you build
Can I get a grant for a house extension?
Not a general one. A council can pay up to €40,000 under the Housing Adaptation Grant for an extension that a person with a disability needs.
Does SEAI pay for any of an extension?
No. SEAI grants are for upgrading the energy performance of the house you already have.
How do people usually fund an extension?
From savings, a mortgage top-up or a home improvement loan, or some of each.
What will the bank ask for?
Usually the drawings and a builder's written price. Have both before you finalise the loan.
Is there any tax relief?
No. The Home Renovation Incentive finished in 2018.
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