Knauf Rocksilk RS80 100mm Building Slab

The Knauf Rocksilk RS80 100mm mineral wool building slab is a robust, standard-density material engineered for superior thermal and acoustic performance across diverse construction applications. With a Euroclass A1 fire rating—the highest classification for non-combustible products—this rock mineral wool insulation delivers outstanding fire safety.

Sized at 1200mm x 600mm with a thermal conductivity of 0.034W/mK, these unfaced slabs provide excellent energy efficiency for new builds and refurbishment work.

The material is naturally odour-free, non-hygroscopic, and resistant to rot, fungi, mould, and bacterial growth. It contains no CFCs or HCFCs, making it an environmentally responsible choice.

Installation is straightforward—simply cut and shape using a large-bladed knife or saw. The Knauf RS80 slab excels in sound absorption, delivering significant acoustic performance alongside thermal benefits.

Ideal for pitched roof construction between rafters, intermediate floors, internal partitions, timber and metal stud walls, and light steel frame infill, this versatile product suits multiple building scenarios.

Product specification

• Brand: Knauf®
• Model: 100mm Rocksilk RS80
• Thickness: 100mm
• Length: 1200mm
• Width: 600mm
• Dimensions: 1,200mm x 600mm x 100mm
• Board Coverage: 0.72m2
• Pack Coverage: 2.16m2
• Pack Quantity: 3
• R-Value: 2.20m2K/W
• Thermal Conductivity: 0.034W/mK
• Density: 80kg/m3
• Colour: Brown
• Material: Rock mineral wool
• Fire Classification: Euroclass A1
• Vapour Resistivity: 5.00MNs/g.m.
• Fire Reaction: Non-combustible
• Building Regulations: Class '0'
• Finish: Unfaced
• Shipping method: Articulated Vehicle ǀ Courier
• Applications: Floor ǀ Wall ǀ Roof ǀ Partitions
• Foil faced: No
• ECOSE Technology: Yes
• ETA Notification: Yes
• Features: Thermal and Acoustic Insulation Performance
• Manufacturer: Knauf Rocksilk®

Made to order Facings

For a factory applied foil or tissue facing please request a quotation using the website form or by calling our agents. We do offer single side or double side foil/tissue facings.

Applications

This versatile mineral wool slab works exceptionally well in pitched roof installations between rafters, separating and intermediate floor constructions, internal stud partitions, and light steel frame systems. Widely used in OEM (Original Equipment Manufacturer) applications for thermal, acoustic, and fire-rated product fabrication, Rocksilk® slabs are available across a range of densities from 45kg/m3 to 140kg/m3, ensuring suitability for virtually any project requirement.

Benefits

• A single product type addresses multiple construction applications.
• Factory-applied foil or tissue facing options are available, expanding the range of suitable uses.
• Rock mineral wool composition delivers superior sound reduction and absorption compared to conventional insulants.
• With a melting point exceeding 1000°C, this rock mineral wool provides extended fire resistance performance relative to standard alternatives.

Info

Browse our full Knauf Insulation range and refine by thickness or coverage using the left-hand filters. For project-specific advice or bulk pricing enquiries, contact us on +4402038839057, email sales@insulationbee, or use our Live Chat service. We're here to help you find the right Knauf loft insulation solution at competitive UK prices.