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100mm Knauf Rocksilk RS45 Building Insulation Slab 1200mm x 600mm 3.6m2 Pack
100mm Knauf Insulation Rocksilk RS45 is a Rock Mineral Wool slab, designed for use in multiple thermal and acoustic applications. It is non-combustible with the best possible Euroclass A1 reaction to fire classification.
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25mm Knauf Rocksilk RS45 Building Insulation Slab 1200mm x 600mm 14.4m2 Pack
25mm Knauf Insulation Rocksilk RS45 is a Rock Mineral Wool slab, designed for use in multiple thermal and acoustic applications. It is non-combustible with the best possible Euroclass A1 reaction to fire classification.
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50mm Knauf Rocksilk RS45 Building Insulation Slab 1200mm x 600mm 7.2m2 Pack
50mm Knauf Insulation Rocksilk RS45 is a Rock Mineral Wool slab, designed for use in multiple thermal and acoustic applications. It is non-combustible with the best possible Euroclass A1 reaction to fire classification.
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75mm Knauf Rocksilk RS45 Building Insulation Slab 1200mm x 600mm 4.32m2 Pack
75mm Knauf Insulation Rocksilk RS45 is a Rock Mineral Wool slab, designed for use in multiple thermal and acoustic applications. It is non-combustible with the best possible Euroclass A1 reaction to fire classification.
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Suspended Floor Insulation RS45
Properly fitted suspended floor insulation helps keep interior spaces warm. It is made for use in any buildings with timber or beam-and-block floors, including modern buildings and period homes. These floors are exposed to an air void beneath them and can lose up to 15% of a property’s heat if left uninsulated.
What is suspended floor insulation?
Also known as underflow insulation for timber or beam-and-block floors, suspended flooring insulation is positioned between the joists of a suspended floor. These floors have an air gap underneath that causes them to lose heat.
Without insulation, that empty space acts like a cold bridge (a pathway that lets heat escape), causing draughts to rise into the room above. When you fit insulation underneath or between joists, the insulation forms a barrier that keeps heat inside.
What is suspended floor insulation used for?
Underfloor insulation for timber floors effectively reduces the amount of heat lost through suspended floors. It is ideal for:
- For installation between joists in older buildings with timber floors.
- New builds that aim to fulfil Building Regulations for energy performance.
- Retrofit projects where you want more comfort and efficiency, but don’t want to replace the whole floor.
Types of suspended floor insulation
Insulation for suspended floors is available in two main types: rigid panels and soft insulation slabs. Both options are available in our suspended floor insulation collection.
Made from materials like PIR, XPS, or EPS for lighter applications where cost-efficiency matters, rigid boards offer excellent compressive strength and thermal efficiency. They are perfect for floors that need to handle higher loads or where a precise fit is required between joists.
Soft Insulation Slabs or Insulation Rolls
Soft insulation slabs and rolls are lightweight, flexible and quick to install. Usually made from glass or mineral wool, they fit tightly between joists. This insulation is excellent at reducing heat loss and sound transfer and is therefore ideal for uneven or older timber floors.
Both underfloor insulation suspended floor boards and flexible slabs deliver reliable, long-term performance. Choose rigid boards for strength and stability, or soft slabs and rolls for flexibility and sound control.
Benefits of insulation for suspended flooring
Installing suspended floor insulation offers several advantages:
- Lower energy bills.
- Increased comfort.
- Sound absorption.
- Moisture protection.
- Environmentally friendly.
Why choose our underfloor insulation for timber floors?
We supply trusted brands that deliver lasting performance across all suspended floor applications.
We provide enough variety to meet various flooring requirements. Whatever type of suspended timber floor insulation you require, you will find it at our store.
Give your floors the upgrade they deserve with high-quality suspended floor insulation from Insulation Wholesale. We deliver within 1-3 working days across the UK, unless stated otherwise on the product page or during checkout. Browse our full range of rigid insulation panels and flexible slabs.
FAQ
What thickness insulation for suspended floor?
The right floor insulation suspended floor setup, including thickness, will depend on the type of insulation used, target U-value, floor design, and load requirements. In most cases, Building Regulations call for 100mm to 150mm of between-joist insulation. Analyse the building spec and check the product’s R-value for optimal performance.
How to install suspended floor insulation?
- Step 1: Remove your floorboards. Check for signs of moisture or mould and replace any that are affected. If insulating an older property, lay a breathable membrane underneath the insulation. This will help block draughts while boosting ventilation.
- Step 2: Fit your suspended floor insulation between the joists. Do not compress soft insulation, as this can reduce its effectiveness.
- Step 3: Secure the insulation using support wires, battens or netting.
- Step 4: Add a vapour control layer if it’s required, then replace the floorboards. Ensure the underfloor void remains well ventilated to prevent condensation and timber decay
How much does suspended floor insulation cost?
Suspended floor insulation prices vary based on coverage per roll or board and the insulation’s thermal rating. Mineral wool generally goes for £20–£30 per roll, while rigid PIR boards range between £25 and £50 per sheet.