120mm Rockwool Hardrock Multi-Fix DD Underlay Slab

Rockwool HardRock Underlay Slab Multi-Fix (DD) delivers high-density, non-combustible thermal insulation for warm flat roofs. Engineered for superior acoustic performance and fire resistance, this proven solution strengthens your roofing system.

This 120mm Hardrock Multi-Fix board reinforces lightweight flat roof insulation applications by minimising sound transmission across the building envelope.

Perfect for high-traffic areas requiring regular maintenance, these 120mm Rockwool Hardrock boards work seamlessly with all roof covering types—torch-on, pour-and-roll, single-ply, EPDM, liquid-applied, and green roofs.

Product specification

• Thickness: 120mm
• Width: 1000mm
• Length: 1200mm
• Pallet Quantity: 10
• Pallet Coverage: 12m2
• Density: 160kg/m3
• Weight/m2: 9.6kg
• Weight: 230.4kg
• Thermal Conductivity: 0.039W/mK
• R-Value: 1.54m2K/W
• Fire Rating (Reaction to Fire): A1(Non-combustible)
• Application: Primary base layer for all systems
• Applications: Torch applied, pour and roll bitumen, single ply and EPDM mechanical or adhered systems, liquid applied systems and green roof

This stone wool insulation board features a mineral-coated white fleece facing, making it compatible with numerous adhered and mechanically fixed waterproofing solutions including bitumen, single-ply, EPDM, liquid membranes, and green roof systems.

Key features include:

• Produces no smoke and will not fuel fire development at any stage, including full fire development.
• Non-combustible per UK building standards, meeting Zurich School and Academy Design guide and HTM05-03 healthcare guidance requirements.
• LPCB approved at the highest level, LPS1181: Part 1 EXT – A rated constructions.
• Outstanding acoustic reduction, absorption, and impact (rain noise) capabilities.
• Satisfies all BB93 (Education) and HTM08-01 (Healthcare) acoustic specifications.
• Acoustic solutions can unlock additional BREEAM credits.
• Maintains dimensional stability throughout its lifespan.
• Delivers consistent thermal performance without blowing agents, featuring zero ODP and GWP.
• Fully recyclable and reprocessable, minimising waste and reducing costs.

Applications

120mm Rockwool Hardrock Multi-Fix Underlay Slab roofing boards perform excellently with these roofing systems:

• Fully bonded, partially bonded, and mechanically fastened single-ply membrane systems, plus EPDM membrane systems.

• Torch-applied, bitumen-based, and mastic asphalt built-up systems.

• Liquid-applied systems.

• Green roof systems.

• Rockwool Acoustic Membrane is a high-density polymer mass layer that, when combined with HardRock Multi-Fix (DD), offers enhanced acoustic performance for the highest specifications.

• Rockwool insulation Acoustic Infills are tissue-wrapped, trapezoidal-shaped trough inserts designed to improve the acoustic absorption of perforated metal decks.

More Information on 120mm Rockwool Hardrock DD Underlay Slab

• Manufaturer Link: 120mm Rockwool Hardrock Multi-Fix DD Underlay Slab
• Browse our comprehensive Rockwool Insulation range and refine by thickness or coverage using the left-hand filters. For expert advice on product suitability for your project or to request a bulk discount quotation, contact us on +4402038839057, email sales@insulationbee, or use Live Chat - Best value Rockwool Insulation in the UK.