Kingspan Kooltherm K108 Partial Fill Cavity Board Insulation

When you're aiming for top thermal performance without compromising space, Kingspan Kooltherm K108 is a smart insulation choice. Designed for use in partial fill cavity wall constructions, K108 offers an impressively low thermal conductivity of 0.019 W/mK—one of the best in its class. This allows you to meet U-value targets with a slimmer insulation board compared to standard alternatives, giving you more flexibility in your wall design. Whether you’re building new or upgrading existing structures, K108 is a practical option. Ideal for building insulation applications, this product helps create an efficient thermal envelope. It also works seamlessly with insulation systems. Its slim profile not only helps reduce the thickness of external walls but can also boost natural daylight in internal spaces by allowing larger window openings. It’s ideal for energy-conscious projects where every bit of space and performance matters.

Benefits of Kingspan K108

Exceptionally thin insulation with excellent thermal performance, perfect for achieving compliance without bulky build-ups. Slimmer walls make room for larger window areas, which can increase natural light inside the building. Designed to maintain a clear cavity, ensuring resistance to moisture penetration and long-term reliability. The low emissivity foil facing adds extra thermal resistance to the cavity, improving overall wall performance. Lightweight and easy to handle, K108 makes installation straightforward and efficient. Compatible with BIM systems to aid digital project planning.

Available Board Sizes & Coverage

50mm thick – 1200mm x 450mm – approx. 5.4m² per Pack 60mm thick – 1200mm x 450mm – approx. 4.32m² per Pack 75mm thick – 1200mm x 450mm – approx. 3.24m² per Pack 100mm thick – 1200mm x 450mm – approx. 2.7m² per Pack

Frequently Asked Questions

1. Can Kingspan K108 be used in all types of cavity wall construction?

K108 is specifically designed for **partial fill masonry cavity walls**. It provides excellent thermal performance while maintaining a clear air cavity, which is crucial for moisture resistance.

2. Does it require any special tools or fixings for installation?

No specialist tools are needed. The boards are **lightweight and easy to cut**, and they fit between standard wall ties. Just make sure the cavity is clean and the boards are installed snugly for best performance.

3. How does K108 compare to full-fill insulation?

While full-fill options may offer slightly higher thermal mass, **K108 excels in moisture resistance and design flexibility**. It’s a great option when you want high performance without filling the entire cavity, especially in wetter climates.

Check out our other products here.

Explore more from our range here.

At JJ Building Materials, we're committed to supplying quality building products at competitive prices, backed by the service and expertise you'd expect from an established independent merchant. Whether you're a trade professional managing large-scale projects or a homeowner taking on a DIY renovation, we're here to help you find the right products for the job.

As part of the JJ Roofing Supplies Group, we build on decades of experience supplying construction materials across the UK. We've expanded beyond roofing to offer a growing range of building materials, including timber, insulation, landscaping products, plumbing supplies, flooring, doors, bricks, fencing, garden buildings and much more – all available to order online with nationwide delivery.

We work with many of the industry's leading manufacturers to bring you trusted products that meet the highest standards of quality and performance. Our team is passionate about providing excellent customer service, competitive pricing and a straightforward shopping experience from start to finish.

When you shop with JJ Building Materials, you can expect:

• Competitive prices on leading brands and quality products.
• Nationwide delivery across the UK
  
• A constantly expanding range of building and landscaping materials.
  
• Friendly, knowledgeable customer support.
  
• A trusted business backed by the JJ Roofing Supplies Group.
  

Every order is personally reviewed by our experienced team to ensure everything is correct before dispatch. We offer delivery from as little as the next working day on selected products, so please refer to the dark blue Estimated Delivery box above for the expected delivery timeframe for this item.

We work with trusted manufacturers and specialist delivery partners to ensure your order arrives safely and on time. You'll receive tracking details once your order has been dispatched, and if we need to confirm any delivery details, one of our team will contact you directly to keep everything running smoothly.

Roof Tiles & Fittings:

We recommend ordering an additional 10% of roof tiles to allow for any breakages that may occur during delivery or handling. Roof tiles are naturally fragile, and having a few extra on site helps prevent delays and ensures your roofing project can be completed without interruption.

Multiple Products from the Same Supplier

If you're ordering multiple products from the same supplier, your order will be dispatched together once all items are ready. This means the longest lead time will apply.

If you need part of your order sooner, please call us on 01202 113233. We can arrange a split delivery, although an additional shipping charge will apply.