Complete Guide to External Wall Insulation in Ireland
External wall insulation, often referred to as house wrapping, is one of the most effective ways to lower your energy bills and improve comfort in Irish homes. Wrap your home in a continuous thermal blanket and claim up to €8,000 in SEAI grants.
What is External Wall Insulation (EWI)?
External wall insulation involves fixing insulation boards directly to the outer brickwork or blocks of a house. The system is mechanically anchored, reinforced with mesh, and covered in a silicone render to protect against weather.
Because EWI is installed entirely on the exterior, it prevents internal disruption and does not reduce indoor room sizes. It wraps the structure completely, eliminating thermal bridges.
Exempted Development Regulations
Irish planning regulations state that external insulation is classed as exempted development. However, you must apply for planning permission if your house is a protected structure or located in an Architectural Conservation Area.
How Much Does External Wall Insulation Cost in Ireland?
EWI installation costs are calculated based on wall surface area. Average prices range between €100 and €180 per square metre.
| House Type | Typical Wall Area (m²) | Average Gross Cost | SEAI Grant Amount | Net Out-Of-Pocket Cost |
|---|---|---|---|---|
| Mid-Terrace House | 60 to 80 m² | €8,500 to €12,000 | €3,500 | €5,000 to €8,500 |
| Semi-Detached (3-Bed) | 100 to 130 m² | €12,500 to €18,000 | €6,000 | €6,500 to €12,000 |
| Detached House | 150 to 200 m² | €18,500 to €28,000 | €8,000 | €10,500 to €20,000 |
| Apartment | 40 to 60 m² | €6,000 to €9,000 | €3,000 | €3,000 to €6,000 |
Key Materials & EWI Systems
The choice of insulation boards determines the thickness needed to meet Irish building regulations.
Expanded Polystyrene (EPS)
Grey graphite EPS is the most popular material for external insulation in Ireland due to its excellent balance of cost and performance.
Mineral Wool (Rockwool)
Mineral wool is a breathable, non-combustible material that provides high fire ratings, making it suitable for boundary walls.
Phenolic / PIR Insulation
Phenolic boards offer premium thermal resistance, allowing thinner installations in tight side paths and alleyways.
Critical EWI Vetting Standards: U-Values & Ventilation
Proper ventilation checks are essential when sealing a home to prevent mold.
Target U-Value (0.27 W/m²K)
To qualify for the SEAI grant, the wall insulation system must achieve a U-value of 0.27 W/m²K or better. Lower numbers represent higher thermal efficiency.
Ventilation Audit Requirements
Wrapping your home stops drafts and traps moisture. Under NSAI rules, insulation contractors must perform a ventilation audit to ensure sufficient room vents are present.
Citable EWI Facts
- 1.External wall insulation systems wrapped around traditional solid block walls achieve Part L compliance by reaching U-values of 0.27 W/m²K or better.
- 2.Sustainable Energy Authority of Ireland grants cover up to €8,000 of the cost for external insulation on detached properties.
- 3.Under Irish planning guidelines, external wall insulation is classed as exempted development unless the property is a protected structure or in an Architectural Conservation Area.
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