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Installing EWI with Kingspan K5

We’re excited to be stocking Kingspan K5 external wall insulation boards for customers to use as part of our systems! As a result of this, we’ve had many questions about how to integrate them with the rest of our materials, most especially which materials to use to install the Kingspan.

If you’re used to doing EWI, then you will find that Kingspan is very easy to install so we’re going to talk a little bit about why you may want to use Kingspan K5 insulation, as well as how you would go about installing it!

What is Kingspan K5?

Kingspan K5 boards are designed specifically for use as part of an external wall insulation system – they are fitted to the exterior of a property using a combination of adhesive and mechanical fixings. While EPS is our most popular insulating material, Kingspan insulation offers different advantages.

Kingspan K5 has a phenolic core (phenolic is a type of plastic), giving it excellent thermal capabilities. In fact, the thermal properties of Kingspan are greater than EPS. When choosing to install EPS insulation, it’s important to remember that 90mm of insulation is required to meet building regulations. On the other hand, Kingspan K5 boards (despite being more expensive than EPS) only need to be 60mm thick to reach building regulations. This means that if space is an issue, Kingspan can be a more advantageous choice.

The other advantage of Kingspan K5 boards is that they are a far denser board with a higher compressive strength. Kingspan insulation is often used for floor insulation due to its strength, so in EWI systems where impact resistance is key Kingspan wins hands down.

How to Install Kingspan K5 External Wall Insulation?

Installing K5 boards as part of an EWI system is easy. We recommend using our Premium Basecoat as an adhesive to secure the boards to the substrate. Although they are relatively lightweight compared to Mineral Wool, K5 boards are still heavier than EPS and therefore require our strongest adhesive.

Our standard method of applying the adhesive should be used for Kingspan. The ‘dot and dab’ method involves applying the adhesive right the way around the perimeter of the board, with three dabs in the middle. Once this has been applied to the back of the board, they should be staggered in the usual formation upwards from the uPVC starter track.

The slight difference with K5 boards is that they require metal screw fixings to secure them to the substrate. Hammer fixings (be it plastic or metal) are more commonly used for EWI, however, because Kingspan K5 boards are a more rigid structure than EPS, the metal screw fixings are a better choice.

  • Starter Track 170mm-240mm (2m)

    £29.26 Excl. VAT
  • WKRET-MET – Metal Pin Screw Fixing (WKR-WKTHERM-S-08115)

    From £49.69 Excl. VAT

Applying Render to Kingspan

Kingspan K5 boards are ideal for use with a lightweight render on top, such as our Silicone Silicate render system. The Premium Basecoat should once again be used within the basecoat reinforcement layer; this should be applied up to 6mm thick with a Fibreglass Mesh embedded within it.

Once the basecoat has dried, it will need priming with the render primer that corresponds with the render.

Once the render primer has dried, you are finally ready to render! You can start applying the Silicone Silicate render using a trowel. Remember to apply the render at a thickness that corresponds with the grain size – so, for example, a 1.5mm grain size render would be applied at 1.5mm thick. Spread the render out and rub it up using a plastic render float to bring out the texture. Once applied, leave the render to dry for a minimum of 24 hours.

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