External Wall Insulation and Render

External wall insulation costs a median €23,219 for a semi or end of terrace in Ireland, €26,500 for a detached house and €14,000 for a mid-terrace, before the SEAI grant of €6,000, €8,000 or €3,500.

How the insulation is finished in render, what the grant needs, and the planning rule since July 2026.

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€23,219SEAI median cost, semi or end of terrace
€8,000SEAI grant, detached house
150 mminsulation allowed without planning
Pre-2011homes built and lived in before 2011

Insulation finished in render

External wall insulation (EWI, or the wrap) fixes insulation boards to the outside of the walls, then a base coat with mesh and a render finish go over them, usually silicone or acrylic. From the road it looks like a newly rendered house; inside, the walls are warmer.

House	SEAI median cost	SEAI grant
Detached	€26,500	€8,000
Semi or end of terrace	€23,219	€6,000
Mid-terrace	€14,000	€3,500
Apartment	€11,300	€3,000

The median costs are SEAI's own figures for homes insulated with the grant. The grant is fixed by house type and paid after the work, on the SEAI wall insulation scheme: the home must have been built and lived in before 2011, every external wall must be done, an SEAI registered contractor does the work, and the grant must be approved before work starts.

Since July 2026, adding external insulation to a house up to 150 mm thick on the front, rear or gable is exempted development (Class 63, S.I. No. 341 of 2026), as long as it doesn't encroach on a public road and doesn't change the look of the house out of character with it and its neighbours.

Insulate, or just render?

Rendering alone doesn't make a wall warmer. Insulation does, and the grant helps pay for it.

Job	Typical price	What moves the price
External insulation and render, 3-bed semi	€12,000–€22,000	Before the SEAI grant of up to €6,000 on a semi
Silicone render (thin coat)	€55–€80 per m²	Base coat and mesh first, then the coloured silicone. Sheds water and dirt
Acrylic render (thin coat)	€60–€80 per m²	Like silicone on a base coat; flexible, wide colour choice
3-bed semi-detached, whole house	€4,000–€10,000	The finish, the state of the old walls, the gable
Detached two-storey, whole house	€7,000–€16,000	Four walls, more scaffold, bays and corners

A guide for typical Irish houses. Your price is fixed by the contractor after they've seen the walls. Nothing is booked until you say yes.

More on rendering

Every job is priced by the contractor after a look at the walls.

€55–€80per m²Silicone renderThin, through-coloured and water-repellent. Never painted.Silicone render →€60–€80per m²Acrylic renderA flexible thin coat in almost any colour.Acrylic render →€50–€75per m²Monocouche renderOne coat with the colour in the mix, scraped to a sandy finish.Monocouche →€1,500–€4,000to re-dash a semiRendering over pebble dashCover it, paint it or remove it: which suits your walls.Pebble dash →€200–€300a day for a plastererRender repairCracks, hollow patches and stains, and when to re-render instead.Repairs →€60–€90per m²Lime renderBreathable, for old stone and brick walls with no cavity.Lime render →

Rendering in every county

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Questions we get asked

How much does external wall insulation cost in Ireland?

SEAI's median cost is €23,219 for a semi or end of terrace, €26,500 for a detached house and €14,000 for a mid-terrace, before the grant.

What grant is there for external wall insulation?

Not for rendering on its own. If the walls are insulated on the outside and then rendered, SEAI pays €3,000 for an apartment, €3,500 for a mid-terrace, €6,000 for a semi or end of terrace and €8,000 for a detached house, approved before work starts.

Do I need planning permission for external insulation?

Usually not since July 2026: up to 150 mm on the front, rear or gable is exempted development under Class 63, if it doesn't encroach on a public road or change the house's character.

Can I just render instead?

Yes, but render alone doesn't insulate. If the walls are cold, insulating and rendering together gets the grant and does both jobs.

Who comes out?

One rendering contractor who covers your county. For the grant, the contractor must be SEAI registered for external insulation: ask.

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