Roof insulation in Ireland: the right method for your roof
Attic floor, rafters, a room in the roof or a flat roof. See where the insulation should go, what it costs and the grant before you give any details.
Free and no obligation. Your plan goes to one contractor, not a list.
- 76%of pre-2011 Irish houses fall short of the roof standard on their BER
- €1,500SEAI attic grant for a semi-D, up to €2,000 detached
- 63 m²the middle roof area on those BER certificates
- 0.16W/m²K, the standard for a pitched roof
Plan your roof insulation
A few quick taps, and your plan fills in as you answer: the right method for your roof, what it costs, the grant and the standard to ask for. Contact details come last, and only if you want a contractor to price it.
Attic floor insulation, semi-d or end of terrace: €1,800 to €2,101 before the €1,500 SEAI grant, so about €300 to €601 to pay.
How the estimate is worked out
Attic floor insulation uses what SEAI-registered contractors were paid for each kind of home in 2026 and what an Irish installer charges, with the SEAI grant taken off. A room in the roof and a flat roof are priced per m² of the area you enter: rafter boards with a plasterboard finish, or a warm roof with a new membrane. VAT is included. Use it to plan with. It isn't a quote: a contractor prices your roof after a survey.
Where the insulation goes in your roof
Each roof in our drawings, with its own page: the method, the cost, the grant and what to watch for.
Attic insulationThe usual job: wool over the joists, a cold attic above, an SEAI grant towards it.
Rafter insulationBoards between and under the rafters, so the whole attic stays warm.
Room in the roofSloping ceilings, knee walls and a small top ceiling, wrapped all round.
Insulating from aboveBoards over the rafters when the slates come off anyway.
Flat roof insulationA warm roof on the deck, or a cold roof with a vented gap.
Garage and extension roofsFlat or pitched, heated or not: what each needs.Your plan, one contractor, your decision
- 1Tell us about the roofWhich roof, what's up there now and the kind of home. The planner shows the method, the cost and the grant before it asks for anything.
- 2One contractor surveys itSend the plan and a single vetted insulation contractor for your area rings to arrange a survey. Your number goes to that one contractor and nobody else.
- 3You decideThe contractor prices the job in writing after the survey. Nothing is booked unless you accept, and the grant is applied for first.
Our price guide
What the common roof insulation jobs cost in Ireland, VAT included.
| Job | Cost, VAT included | What it comes to |
|---|---|---|
| Attic insulation, semi-detached house | €1,800–€2,101 | SEAI grant €1,500, so about €300–€601 to pay |
| Attic insulation, detached house | €2,400–€2,700 | SEAI grant €2,000, so about €400–€700 to pay |
| Room in the roof, rafter boards and plasterboard | €100–€180 per m² | 30 m² of ceiling and walls: €3,000–€5,400 |
| Warm flat roof with a new membrane | €130–€190 per m² | A 25 m² extension roof: €3,300–€4,800 |
Every method, per m² and per home: roof insulation cost. Attic only, by home and by size: attic insulation cost. The grant: attic insulation grant.
How well insulated are Irish roofs?
From the roof U-value on every BER certificate for a house built before 2011.
- 24%meet the 0.16 W/m²K level
- 29%are close, 0.17 to 0.30
- 40%are poor, 0.31 or worse
- 7%show no insulation at all
Of 586,283 certificates, 87% describe a pitched roof insulated at the ceiling, 6% at the rafters, 5% a room in the roof and 2% a flat roof. Houses built from 1978 to 1993 do best: 36% meet the standard, against 17% of houses built before 1978. Your county's figures are on its page.
Before you start
How much does roof insulation cost in Ireland?
Insulating an attic floor costs €1,800 to €2,101 for a semi-detached house and €2,400 to €2,700 for a detached one, before an SEAI grant of €1,500 or €2,000. Insulating a room in the roof at the rafters, with a plasterboard finish, runs €100 to €180 per m², and a warm flat roof with a new membrane €130 to €190 per m². VAT is included. The full price guide.
Should I insulate the attic floor or the rafters?
Insulate where the warmth should stop. If the attic is only for storage, insulate the attic floor and keep the attic cold and ventilated. If people use the space under the roof, insulate at the rafters, all round the room. A flat roof is usually insulated on top of the deck as a warm roof, ideally when it is re-covered.
Is there a grant for roof insulation?
SEAI's individual grant for roof insulation is for the attic floor: €2,000 for a detached house, €1,500 for a semi-D or end of terrace, €1,400 for a mid-terrace and €1,100 for a top-floor apartment, with higher amounts for first-time buyers of an older home and some people on welfare payments. Rafter and room-in-roof insulation are grant-aided only as part of a One Stop Shop whole-home upgrade.
How much insulation does an attic need?
For new work, the Building Regulations ask for 0.16 W/m²K in a pitched roof, whether it is insulated at the ceiling or along the slope, and 0.20 W/m²K in a flat roof. About 300 mm of mineral wool on an attic floor gets there.
Is spray foam a good way to insulate a roof?
It can work at the rafters when it is the right foam, fitted with a ventilated gap under the felt, but it is hard to inspect and harder to remove, and surveyors and some lenders ask about it. Boards or wool are easier to check and to grant-aid. Spray foam insulation.
Who rings me if I send my plan?
A single vetted insulation contractor for your area, who already has your answers and our estimate. Your details go nowhere else.
How long does attic insulation take?
Most attic floors are done in a day once the grant is approved and the attic is cleared. A room in the roof takes longer, with plastering.
Every guide and county page
Methods
Costs, grants and rules
Keep the heat under your roof
Pick the roof, what's there now and the home to see the method and the cost. When you want a firm price, your plan goes to a single vetted insulation contractor for your area.