External Wall & Cladding Insulation

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.

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What Is Exterior Wall Insulation?

Insulating a wall's external surface is commonly referred to as external wall insulation. It involves putting an insulating material layer on the wall then topping it with a specific sort of render (plasterwork) or cladding.

By installing external wall insulation, you are effectively coating your house with a large sheet of insulation. This method decreases the amount of cold air that can seep through cracks or openings in masonry walls, therefore minimising the occurrence of cold bridging.

Seeing as homeowners and commercial site managers lose around 35% of the heat in their spaces through walls, wall insulation should be the first port of call when considering where to install thermal insulation. 

The right external wall insulation (EWI insulation) can eliminate a third of your energy bills and keep your space warmer for longer. Browse through our catalogue of external insulation cladding in thicknesses 20mm-100mm to discover a long-term solution to high heating bills.

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


Benefits of Exterior Wall Insulation

  • Unlike internal insulation, it can be installed with minimal disruption
  • It won't encroach on a building's floor space - you don't want to lose valuable floor space by insulating internally 
  • Can be used to improve the aesthetic of your external walls - offering an improved and cleaner façade to the exterior of your home.
  • Protects the fabric of your property's brickwork, increasing its overall lifespan
  • Improves energy efficiency, reducing heating costs and carbon footprint


Kingspan Kooltherm K5 External Wall Board

Kingspan Kooltherm K5 External Wall Board is a premium performance insulation solution for installation on external walls.

Made up of a fibre-free thermoset phenolic core, this rigid insulation board is suitable for use behind traditional and lightweight polymer-modified renders and dry cladding systems.

Kingspan Kooltherm K5
boards feature a glass tissue face on either side, and are resistant to the passage of water vapour. They are manufactured using a low GWP blowing agent that has zero ODP. What's more, they also boast a Euroclass rating of C-s1,d0, meaning it has a limited contribution to fire.

These boards in the Kooltherm range have a thermal conductivity of between 0.020 W/mK and 0.023 W/mK. 

What is Cladding Insulation? 

The term cladding refers to the outer casing of buildings; external wall insulation cladding has no impact on the structural integrity of the building itself. Cladding is an outer layer of material that is often used to enhance thermal efficiency and protect buildings from the elements. 

It can also be used for aesthetic purposes, to give a particular building or structure a certain look. Common materials used for cladding include stone, brick, metal, and wood.

Frequently Asked External Insulation Cladding 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.