Knauf Rocksilk RS45 - Rock Mineral Wool Acoustic and Thermal Insulation Slab

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product brand
Brand: Knauf Insulation
Country of Manufacture: United Kingdom
In Stock
Product Code: KFRS4
Est. Delivery: 2-3 Working Days
Shipping cost displayed in basket
£33.34 (ex VAT)
£40.01 (incl VAT)


Rocksilk RS45 building slabs by Knauf Insulations offer excellent thermal insulation in every application, thanks to their low thermal conductivity. These insulation slabs also have superior soundproofing abilities. Rocksilk RS45 is also non-combustible in nature. It has the highest possible fire rating - A+ by Euroclass.

Rocksilk RS45 adapt easily to any imperfections in the substrate and can be ‘knit’ together. Air gaps are eliminated, as a result, which results in better insulation. They perfectly fit into all framed applications and can be used in any type of structure, whether commercial or residential. 

Thermal and acoustic insulation slabs by Knauf are lightweight, easy to cut and install. They are moisture-resistant, rot-proof and odourless. They do not support the growth of moulds, fungi, vermin or other organisms. 

The rock mineral wool insulation from Knauf Insulations is made more environmentally friendly and human-friendly with ECOSE® Technology. Mineral wool insulation manufactured using this bio-binder based technology uses up to 70% less energy with no added formaldehyde or phenol. As a result, the insulation slabs produced release very low levels of dust, improving air quality.  Ecose technology also makes Rocksilk slabs easy to handle and soft to touch. 

Product Specification:

  • Length: 1200mm
  • Width: 600mm


Sheets in a pack

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Key Features:

  • Rocksilk RS45 insulation slabs provide excellent thermal and acoustic insulation.
  • Excellent soundproofing abilities enable the product to achieve high degrees of sound reduction. Lightweight, easy to use slabs that have versatile applications.
  • Non-combustible A1 Euroclass Reaction to Fire classification.
  • Manufactured using ECOSE technology - soft to touch and improves air quality
  • Versatile applications. Perfectly suited for a wide range of specifications, uses, and performance needs.
  • Non-hygroscopic, odourless and rot-proof slabs.
  • They can be easily cut to the desired size, with a knife or saw.


  • Knauf’s rocksilk provides excellent floor insulation. They offer excellent insulation to ground floors, internal floors and separating floors.
  • They can also be used to provide exceptional internal wall insulation. Can be used to insulate partitions, Timber frame walls, light steel frame walls
  • They are also ideal for pitched roof insulation at rafter levels and fabrication. 

Product Details:

Material: Rock mineral wool.

Thermal Conductivity : 0.034 -0.035 W/mK

Thermal Resistance: 1.45m2K/W

Surface Spread of Flame: Class 1

Vapour Resistivity: 5.00 MN.s/g.m

You can find all information relating to Rocksilk RS45 here


  • A1 Euroclass Fire Rating
  • Eurofins Gold
  • CE Marking
  • Green Guide Rating A+


  • Knauf Rocksilk45 is made using eco-friendly ECOSE technology.
  • These slabs are free of CFCs, HCFCs, and other elements that could deplete the ozone layer. They have no ODP, thus making it more environmentally friendly.

Handling and storage 

  • Rocksilk RS45 Building Slabs are lightweight, easy to handle and install.
  • Rocksilk Slabs are packaged in recyclable polythene (4-LDPE) which is designed for short-term storage.
  • Ideally, the product should be either stored indoors, under cover or off the ground on-site for longer-term protection.
Average Customer Rating
Overall 5.0

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