Knauf Insulation Loft Insulation

Learn more about loft insulation

Loft insulation acts as a thermal barrier, trapping heat within your living space during winter and keeping it out during summer. Most modern UK homes utilise glass or mineral wool, which are manufactured from recycled glass or volcanic rock melted down and spun into a fibrous structure. This structure creates millions of tiny air pockets that obstruct the flow of heat. Beyond temperature control, quality insulation can provide a critical fire safety layer and helps soundproof your home against external noise.

 

Slashing your energy bills starts at the top. With approximately 25% of household heat escaping through the roof, high-quality loft insulation is the most cost-effective way to improve a home’s thermal performance. Our professional-grade range includes flexible mineral wool rolls and high-density slabs designed for easy friction-fitting between joists.

 

Typical uses

 

• Between joists: The most common application for unfinished lofts to prevent heat rising into the roof void.

• Acoustic dampening: Reducing sound transfer between floors or from external sources like rain on the roof.

• Top-ups: Layering new insulation at right angles over older, thinner material to reach the recommended 270mm depth.

• Internal partitions: Using mineral wool slabs within stud walls to improve thermal and sound privacy between rooms.

 

How to choose the right loft insulation

Selecting the right material depends on your specific loft access and goals. Glass wool rolls are lightweight and cost-effective, making them ideal for large, open joist areas. Stone wool (mineral wool) slabs offer higher density, providing fire resistance and acoustic performance, which is perfect if you are creating a home office or hobby room. Always check the R-value (thermal resistance); the higher the number, the better the material is at preventing heat loss.

 

Before you order

 

• Measure the centres (the distance between your wooden joists). Most rolls are pre-perforated to fit standard UK joist widths of 400mm or 600mm to minimise cutting. 

• Ensure you have the correct PPE, including a mask, goggles, and gloves, as fibrous materials can cause skin and lung irritation. 

• Check your current insulation depth; if you have less than 270mm, you will need to order enough to top up to this level to comply with current best practices for energy efficiency.

 

Explore our range of loft insulation

Our collection is curated from trade-trusted brands for durability and ease of installation. We stock various thicknesses to help you meet building regulations in one or two layers. With bulk delivery available directly to your site or free branch collection across our UK network, getting your project started is simple.

Whether you are topping up existing layers to meet modern 270mm standards or starting a fresh renovation, these materials provide exceptional fire resistance and acoustic dampening. Choosing the right thermal insulation not only creates a consistent indoor climate year-round but also significantly reduces your carbon footprint.

Explore our full insulation range today to find the perfect thickness for your project and start saving.