Basket

Building Insulation

(166 products)

Save on heating bills this winter and make your house energy efficient with our range of Knauf, Isover, Celotex and Recitcel insulation. We have everything from loft insulation to floor insulation and everything in between - shop our wide range of loft, wall, cavity and acoustic insulation all with free delivery on orders over £500, or contact us for help selecting the right insulation for your job.


Quality Insulation from Trusted British Manufacturers

Whether you're insulating a loft, upgrading your walls, or tackling a new build, choosing the right insulation transforms your property's energy efficiency and comfort. At DIY Building Supplies, we take the complexity out of insulation selection, offering expert advice alongside premium products from Britain's leading manufacturers including Celotex, Kingspan, Knauf, Rockwool, Recticel, and Isover.

Why Choose Our Insulation Range?

Expert Technical Support Our experienced team doesn't just sell insulation - we help you specify the right solution for your project. From U-value calculations to building regulations compliance, we're here to ensure your insulation performs optimally for decades to come. Need guidance on thermal bridging, vapour control, or condensation risk? We've got you covered.

Premium Brands, Competitive Prices We've built strong relationships with the UK's most trusted manufacturers, allowing us to secure exceptional prices on market-leading products. When you choose Celotex PIR boards, Rockwool mineral wool, or Kingspan multifoil insulation from us, you're getting authentic, high-performance materials at genuinely competitive rates - backed by full manufacturer warranties.

Comprehensive Product Range

  • PIR Insulation: Celotex and Kingspan rigid boards delivering outstanding thermal performance with slim profiles
  • Mineral Wool: Rockwool and Knauf solutions offering excellent fire resistance and acoustic properties
  • Multifoil Insulation: Reflective, space-saving options ideal for pitched roofs and tight spaces
  • Polystyrene Insulation: Cost-effective solutions for floors and below-ground applications
  • Natural Insulation: Sustainable options including sheep's wool and wood fibre boards

Making Insulation Simple

We understand that insulation specifications can feel overwhelming. That's why we've designed our service around your needs. Tell us about your project - whether it's achieving Part L compliance for a new extension, upgrading a period property, or improving comfort in your home - and we'll recommend the precise products and quantities you need.

Our team handles the technical details: checking compatibility with existing structures, ensuring adequate ventilation, and confirming your chosen solution meets current building regulations. You focus on your project; we'll make sure you have exactly what you need, delivered when you need it.

Delivery Across Mainland UK

Based in Stapleford, Nottingham, we ship insulation materials throughout mainland UK. Our reliable logistics network ensures your order arrives safely and on schedule, whether you're a DIY enthusiast in Manchester or a trade professional in Cornwall.

Get Started Today

Ready to improve your property's thermal performance? Browse our comprehensive insulation range, or speak with our knowledgeable team who can guide you through product selection, calculate quantities, and ensure you're specifying the right solution for your specific requirements.

Need expert advice? Contact our team today - we're here to help you get the job done right, with quality materials at competitive prices.

Frequently Asked Questions

View our help & advice
Types of Insulation

There is a vast array of insulation suitable for all types of uses in home and commercial construction projects, though some of the most common types are loft insulation, cavity wall insulation and floor insulation, as well as PIR insulation board which can be used for a variety of different purposes.

Loft Insulation

Loft roll, also known as loft insulation roll or loft insulation blanket, is a type of insulation material typically made from mineral wool, fiberglass, or recycled polyester fibres. It comes in rolls of varying widths and thicknesses and is designed to be laid between the joists or rafters in the loft space of a building to prevent heat loss. Our most popular Loft Rolls are made of glass mineral wool, which is designed to be more breathable and easier to handle and install, and are manufactured by Knauf and Isover.

Acoustic Roll

Acoustic roll, also known as sound insulation roll or acoustic insulation blanket, is a type of insulation material designed to reduce the transmission of airborne noise between rooms or floors in a building. Typically made from materials such as mineral wool, fiberglass, or recycled polyester fibres, acoustic roll comes in rolls of varying thicknesses and densities. To install acoustic roll, simply roll it out evenly between the joists or studs in walls, floors, or ceilings, ensuring it fits snugly without any gaps. Our most popular acoustic roll is manufactured by Knauf and Isover, and are made from a glass mineral wool.

Cavity Wall / Slab Insulation

Cavity insulation refers to the process of insulating the gap or "cavity" in homes or buildings with cavity walls, which consist of two layers of masonry (such as brick) with a hollow space in between. Cavity insulation materials, such as mineral wool or foam boards, are inserted into this void to reduce heat transfer through the walls.

Our most popular types of Cavity wall insulation are Knauf Dritherm, Isover Cavity Wall Slab and Celotex Thermaclass.

PIR Board Insulation

Polyisocyanurate (PIR) insulation is a type of rigid foam insulation material known for its excellent thermal performance and fire resistance properties. PIR insulation is commonly used in a variety of building applications, including roofs, walls, floors, and ceilings. Its high thermal resistance, light weight and relatively thin profile make it particularly well-suited for areas where space is limited. Our two most common PIR Boards are Celotex PIR Boards, and Recticel PIR Boards.

Floor Insulation

Common materials used for floor insulation include rigid foam boards (PIR), mineral wool or EPS (Expanded Polystyrene). Floor insulation is particularly important in buildings with suspended floors or over unheated spaces such as cellars crawl spaces, or garages. Our most popular floor insulation is PIR board, which has a variety of different uses, although we also offer a more basic EPS board.

Roof Insulation

Roof insulation and loft insulation serve similar purposes but are applied in different areas of a building. Roof insulation refers to the insulation installed within the roof structure itself, typically between the rafters or on top of the roof deck, aiming to prevent heat loss through the roof and maintain a comfortable indoor temperature. This type of insulation is particularly important in pitched or sloped roofs where space between the rafters is limited. Our PIR Insulation Board is well suited to this purpose as it is light weight and easily cut to size, with very effective insulating properties.

Mineral Wool vs Fibreglass Insulation

Mineral wool and fiberglass are two common types of insulation materials with distinct characteristics. Mineral wool, made from natural rock or recycled slag, offers excellent fire resistance and sound absorption properties, making it ideal for both thermal and acoustic insulation. It is denser and heavier than fiberglass, providing better resistance to compression over time. Fiberglass insulation, made from fine glass fibres, is lightweight, flexible, and typically less expensive than mineral wool. It also offers good thermal insulation properties and is commonly used in residential and commercial buildings. While both materials effectively reduce heat transfer, mineral wool tends to be preferred in applications.

What is Glass Mineral Wool Insulation

Glass mineral wool, also known as fiberglass insulation, is a type of insulation material made from fine strands of glass fibres bonded together. These fibres are often arranged in a mat-like structure, providing excellent thermal insulation properties by trapping pockets of air within its structure. Glass mineral wool insulation is widely used in residential and commercial buildings to improve energy efficiency, reduce heat loss, and enhance acoustic performance. It is available in various forms such as rolls, batts, and loose-fill, making it versatile for different applications including walls, ceilings, floors, and roofs. Additionally, glass mineral wool is non-combustible, resistant to moisture, and generally safe to handle, though proper protective gear should be worn during installation due to its potential for skin irritation and respiratory issues if fibers are released into the air.

How to Calculate U Value

The U-value (thermal transmittance) of a building component such as a wall, roof, or window, measures its thermal conductivity or how easily heat can pass through it. The lower the U-value, the better the insulation. To calculate the U-value, you typically need to consider several factors, including the materials used, their thicknesses, and any air gaps. A general formula for calculating the U-value:

U = 1 over R

Where:

  • U = U Value
  • R = The total thermal resistance of the building component, including all layers of materials and air gaps.