External Wall Insulation

(3 Products)

External wall insulation sees an insulation material applied to an existing wall that is then weatherproofed with cladding or render. A welcome byproduct of the process is that it improves a property's thermal efficiency whilst giving it a complimentary facelift, improving the aesthetic appeal and exterior of a building. Unlike insulating internal walls, external wall insulation is a non-intrusive procedure that does not require property entry. We stock popular Kingspan Kooltherm external K5 insulation boards.

Find Out More About Our Types of External Wall & Cladding Insulation
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What is External Wall Insulation?

External wall insulation is a method that involves the application of an insulating layer onto the outer surface of an existing wall. 

Typically, this insulation layer is then finished with either a coat of render or alternative cladding to safeguard it from external elements. This approach is often preferred for properties with solid walls, where traditional cavity wall insulation is not a viable option. 


Benefits of External Wall Insulation

  • Enhanced Thermal Efficiency: Reduces heat loss and lowers energy bills.
  • Improved Comfort: Mitigates draughts, ensuring year-round cosiness.
  • Minimal Interior Disruption: Installation doesn't disturb your living space.
  • Preservation of Internal Space: Maintains valuable floor area.
  • Contribution to Thermal Mass: Regulates indoor temperatures.
  • Enhanced Weatherproofing and Sound Resilience: Creates a quieter, weather-resistant environment.
  • Prolonged Wall Lifespan: Shields walls from weather-related damage.
  • Reduced Condensation: Enhances indoor air quality, and minimises moisture issues.


How Is External Wall Insulation Installed? 

  • Insulation boards are cut to the appropriate dimensions, and adhesive is applied. The boards are then secured onto the walls in a similar pattern to masonry brickwork
  • After being fastened with adhesive, the boards are then drilled into position. Self-tapping screws are typically used in this instance
  • A bonding agent is then applied on top of the insulation (which will add a weather-resistant layer) and an insulating mesh is then fixed to the agent to secure everything together
  • Once set, it’s sanded and painted in primer before receiving a render and final colour


Understanding Cladding Insulation

The term "cladding" refers to the outer casing of buildings, which has no impact on the building's structural integrity. 

Cladding is an outer layer of material used to enhance thermal efficiency and protect buildings from environmental elements. It can also serve aesthetic purposes, giving a specific building or structure a distinctive appearance. Common cladding materials include stone, brick, metal, and wood.


Frequently Asked External Wall & Cladding Insulation Questions

Is External Wall Insulation Fireproof?

All insulation materials have a Euroclass rating. The Euroclass rating was designed to combat the lack of regulation for insulation materials across Europe. External wall insulation boards have to undergo up to five different tests to achieve a Euroclass rating. Insulation that has an A1 rating is non-combustible, and insulation that has an F rating is the most combustible that a material can be. 

We stock Kingspan Kooltherm insulation boards for external walls and cladding. They contain a fibre-free thermoset phenolic foam. When fire makes contact with phenolic insulation, two reactions happen. 

Pyrolysis (thermal decomposition) occurs and a black scorch mark appears on the board at the point of contact. The boards in the Kooltherm range are not fireproof, but they do have a rating that lands in the middle of the scale. 

Kingspan Kooltherm K5 wall insulation boards have a Euroclass rating of C, which means they have limited contribution to fire.

Is External Wall Insulation Waterproof? 

Phenolic boards are water-resistant. They have a closed-cell structure and only absorb around 2% of moisture. They are also faced with either glass tissue or composite foil, which both function as an extra layer of protection for your building. 

Kingspan Kooltherm K5 is designed for a range of purposes. It can protect small domestic properties and large commercial properties alike from the elements. 

We recommend phenolic external wall insulation cladding for those who want to reduce their heat consumption in areas with high rainfalls. 

How to Install Exterior Wall Insulation?

We discourage homeowners from installing solid wall insulation themselves. In most cases, homeowners employ professionals to install external solid wall insulation. This type of insulation can also change the outward appearance of your home, which may require planning permission. 

The installation process is complicated and involves lots of different steps. Professionals have to undertake render tests, remove pipework, and protect windows before they can even think about installing external wall insulation. When it comes to high-performance thermal materials, it pays to speak to the experts.

What Type of Walls Can External Insulation Be Fitted To?

External insulation is specifically designed to be installed in solid-wall properties on solid brick walls or block walls (man-made masonry). Unlike cavity walls, solid walls feature no gap, so they can't be filled with cavity wall insulation.

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