The external walls cover the largest surface area of any building, including the roof, making them the primary area for preventing heat loss.
Poorly insulated walls are the main source of heat loss. With assistance from a professional, your living and work spaces can be warm, energy-efficient, and meet modern building standards.
Additional advantages include good acoustics, interior comfort, and fire safety. Learn everything you need to know about external wall insulation solutions and their benefits.
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Why is external wall insulation important?
Installing external wall insulation can help you to reduce heat loss.
External walls represent, on average, about 40% of all sources of heat loss, and this figure is significantly higher in buildings with recuperated ventilation.
Outer walls are not only an aesthetic element of architecture but they also enhance energy efficiency and maintain a favourable microclimate in the interior space. That is why the insulation of the façade must be properly designed and made with quality materials of adequate insulation thickness.
What materials are used?
“Breathing” insulations have become increasingly popular and preferred for residential buildings. That is why we recommend the use of expanded polystyrene and mineral wool to insulate the exterior of your home.
Expanded Polystyrene (EPS)
EPS is a microporous synthetic organic material that consists of 95% air trapped in tiny spheres within the polymer lattice.
EPS exhibits excellent thermal insulation properties and strength. It is available as boards up to 100 cm wide, 250 cm long, and 1 to 60 cm thick, and can be laminated with waterproof and adhesive materials.
Graphite-enriched EPS (grey) enhances thermal and noise insulation and increases radiation resistance by incorporating graphite molecules into the polymer.
Mineral Wool
Mineral wool is produced by melting basalt rocks at 1500 °C. It is eco-friendly and non-combustible, rated class A1 for fire resistance. Its fibres are oriented to provide effective sound insulation in both contact and ventilated facade systems.
The main parameters for comparing different materials for external insulation are thermal conductivity, ageing resistance, and flammability.
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Installation process
To effectively install external wall insulation, careful preparation and precise application techniques are essential. It’s best to trust the professionals who have the knowledge, insulation products, and instruments required for the job.
Here’s a step-by-step guide on what to expect from the installation process.
1. Cleaning and preparation of the base
Before beginning any renovation work, professionals will clean and prepare the walls. They’ll remove mud, dust, old plaster, and any other debris that could hinder the adhesion of insulation boards.
This can be achieved using pressurised water, sanding or mechanical fixings. Areas with moss or mould are also treated with biocides to prevent future issues
2. Alignment and inspection of the foundation
Professionals will inspect the foundation by tapping with a hammer to locate areas where old plaster has loosened. They will remove and repair these areas with appropriate materials like glue or lime-cement plaster.
The old plaster around doors and windows will be removed to accommodate thicker insulation boards without affecting the frames. Professionals will fill deeper dents with an adhesive solution for stability.
3. Priming the facade
Before installing insulation boards, the facade needs to be primed with a deep-penetrating primer. This step enhances adhesion and strengthens the base for better insulation effectiveness.
4. Adhesion testing
A simple adhesion test will ensure the base’s strength after priming. Affix Styrofoam boards with thermal insulation glue in random places on the surface.
After allowing sufficient drying time (typically three days), a professional will test the bond by attempting to peel off the boards. A secure bond indicates proper adhesion; if boards peel off with the glue layer, additional reinforcement is necessary.
5. Installation of plinth profile
Before applying insulation boards, the experts will install a plinth profile. They’ll determine the appropriate range from the ground, level it carefully, and fix it to the facade using dowels. Stability and protection against fire, moisture, and pests will be ensured by securely fastening the profiles with mounting clips.
6. Preparation and application of thermal insulation glue
The thermal insulation glue must be prepared. Mix a 25 kg bag with approximately 5.5 litres of clean cold water using a construction mixer. Professionals know how to avoid diluting the mixture to maintain its adhesive quality.
7. Application and levelling of insulation boards
The glue is applied evenly to the insulation boards based on the surface type. The boards are levelled with a spirit level to maintain uniformity throughout the facade.
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8. Filling and sealing joints
To prevent thermal bridges and ensure optimal insulation performance, experts will seal the joints between insulation boards with insulating material. If you are doing your external wall insulation yourself, avoid using adhesive solutions for filling, as this can lead to cracking over time.
9. Reinforcement and finishing touches
The insulation boards will be secured with dowels to reinforce attachment and prevent detachment, especially in tall buildings or areas prone to high winds. The dowels should be appropriate length based on the board thickness and facade conditions.
10. Application of putty and decorative plaster
After allowing sufficient drying time for the insulation boards, it’s time for the putty and the reinforcing mesh. The putty is mixed thoroughly with cold water and applied in a 3 mm layer using a construction comb. The mesh should be laid smoothly, ensuring adequate overlap and reinforcement around windows and doors.
11. Priming and application of decorative plaster
After the putty has completely dried, the outer surface is primed by applying the primer evenly with a roller and brush. This should dry before applying decorative plaster. Professionals will select a suitable render coat, taking into account the weather conditions in your area and the type of building.
Our experts at IVCG Renovations follow all these steps to ensure effective home insulation for your home or business improvement. This not only enhances the appearance of your property but also improves its energy efficiency and comfort.
Source: elements.envato.com
Is external wall insulation a good idea?
In most buildings, the outer walls experience the highest heat loss or gain. Insulating external walls can significantly enhance energy efficiency, cut CO2 emissions, and reduce heating or cooling expenses.
External existing walls vary in type, from contact facades to ventilated systems in residential, commercial, and industrial buildings. Each type has its pros and cons, and the choice depends on the building regulations.
What are the drawbacks of external wall insulation?
Despite its advantages, external insulation has two main drawbacks:
- High initial cost – external wall insulation cost can seem high at first due to labour and material prices. Additionally, correcting defects such as cracks and removing previous insulation may be necessary. Despite the high initial costs, long-term energy savings balance this investment.
- Maintenance challenges – accessing the wall for repairs can be more challenging compared to a wall without insulation. However, external insulation protects the walls and helps prevent problems.
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What are the benefits of external wall insulation?
External wall insulation brings numerous benefits and comfort to you and your home.
Here are the main ones:
- Improved appearance of the building – this can also increase its value.
- Lower bills – thanks to insulation, energy consumption will be lower, which also lowers bills. Additionally, your summers will be cooler and your winters – warmer.
- Noise isolation – noise from passing vehicles is often a nuisance for most people. External insulation limits the impact of external noise in the building.
- Lower humidity – well-made insulation acts as a barrier against moisture and prevents the problems that arise with it.
- Extending the life of the building – the external insulation is easily replaced and repaired, which means that the external walls are protected at all times.
- Higher resale value – insulation is not only functional but also a good investment. A well-insulated property commands a higher price when it comes time to sell.
As you see, external wall insulation can bring you unexpected pros that greatly outweigh the cons.
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Frequently Asked Questions
Can external wall insulation be used in all buildings?
EWI is suitable for any building with solid walls. Most of the houses built before 1920 are made of stone or brick without cavity walls. For these homes, external insulation is necessary to reduce heat loss. If the property needs cavity wall insulation, experts will inject insulation material into the cavity from the outside.
How long can external wall insulation last?
Properly installed insulation by a professional can last up to 40 years, depending on the quality of the materials and the installation method. Regular maintenance will extend its life.
Which is better, internal or external wall insulation?
External insulation provides good energy efficiency, while internal wall insulation is easier to install and less expensive. Our advice is to use both external and internal insulation to maximise the benefits.
Do I need planning permission for an external wall insulation project in the Cork and Galway areas?
External wall insulation doesn’t count as an enlargement of your property and is considered ‘permitted development’. This means that planning permission isn’t usually required to start the work.
