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Why choose External Wall Insulation?
External wall insulation is applied to the outside of the walls and is normally accompanied by an external render, installed by a dedicated render system provider. It is ideal for retrofit projects and improving the thermal performance of existing solid wall buildings.
Can external wall insulation cause damp?
When designed and installed correctly, external wall insulation should not lead to damp problems.
Before any work is carried out on your home, a full survey should be carried out, including a review of the condition of your home to check that there aren’t any pre-existing issues like poor pointing, damaged or cracked bricks, leaky guttering or signs of damp. These issues will all need to be fully addressed, and your home in good condition, before the EWI is installed.
The survey should also check that your home is well ventilated. Many homes have been made more airtight overtime due to changes such as replacing original single-glazed windows with double glazing. Whilst this can help to cut out unwanted draughts, it can also cause moist air to get trapped in your home. The survey should make recommendations such as installing trickle vents on windows, shaving the bottom of internal doors or fitting extraction fans in kitchens and bathrooms.
Once all these works are complete, your EWI can be installed by a suitably qualified installer.
Specialist insulation which is resistant to ground moisture penetration (such as Kingspan GreenGuard GG300) may need to be fitted at low levels around the damp proof course to prevent rising damp. Your installer should also carefully plan for junctions around windows and doors to ensure there are no gaps where water can get in, and ensure the insulation itself is installed so that it is tightly jointed with no gaps.
Does Kingspan Insulation have a product suitable for external wall insulation systems?
Kooltherm K5 External Wall Board has a thermal conductivity of as low as 0.021 W/mK, making it a thinner alternative to other commonly used external wall insulants. Using thinner external insulation could allow more daylight into a building (when compared with thicker alternatives) and may reduce the amount of remediation needed to accommodate insulation on the external walls. The boards are suitable for use behind both traditional and lightweight polymer modified renders.
Aerowall Platinum is a rigid expanded polystyrene (EPS) insulation board. It has a thermal conductivity of 0.031 W/mK, which means you will need a thicker layer of insulation to meet your required thermal performance, compared with using a higher performing material, like Kooltherm K5.
K-Roc External Wall Slab is a rock mineral fibre insulation, with a thermal conductivity of 0.037 W/mK, which also makes it thicker than Kooltherm K5 to meet the same level of performance for your wall. It has a European Classification reaction to fire rating of A1, which makes it suitable for applications where enhanced fire performance is required.
Are there grants available for external wall insulation?
The Kingspan Insulation One Stop Shop helps homeowners improve their homes energy efficiency by providing a comprehensive, end to end solution for domestic retrofit and refurbishment projects.
The Kingspan Retrofit Team can offer advice, organise assessments and manage the whole project from start to finish. They also provide access to a range of grants offered by the SEAI (Sustainable Energy Authority of Ireland) to support your home energy upgrades.
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Page updated 19/12/2025
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