Rockwool Hardrock Multi-Fix (DD)

The Rockwool Hardrock Multi-Fix. Manufactured to have exceptional acoustic and fire-resistant properties as well as being compatible with almost all flat roof applications. The Hardrock Multi-Fix is the ideal solution for flat roof applications where meeting acoustic specifications are crucial.


  • The Rockwool Hardrock Multi-Fix has an A2-s2, d0 reaction to fire 
  • Thermal conductivity of 0.039w/mK 
  • Water vapour resistance of 5.9 MNs/gm
  • Compliant with BS EN 13162, ISO 14001.

*Always Refer Back To The Manufactures Specification Document

Download Specification

A uniquely versatile solution suitable for all roof covering types – torch, pour and roll, single ply, EPDM, liquid applied and green roofs – new-build and refurbishment.

Standards and approvals

ROCKWOOL HARDROCK® Multi-Fix (DD) roofing boards comply with the requirements of BS EN 13162, ‘Thermal insulation products for buildings, factory made mineral wool (MW) products specification.’


As an environmentally conscious company, ROCKWOOL promotes the sustainable production and use of insulation and is committed to a continuous process of environmental improvement. All ROCKWOOL products provide four benefits beyond thermal performance.


Relying on entrapped air for its thermal properties, ROCKWOOL insulation does not contain (and has never contained) gases that have ozone depleting potential (ODP) or global warming potential (GWP).

ROCKWOOL therefore complies with the relatively modest threshold of GWP<5 included in documents such as the Code for Sustainable Homes. ROCKWOOL offer a recycling service for the HARDROCK® Multi-Fix (DD) roof boards. We are happy to discuss the individual requirements of contractors and users considering returning ROCKWOOL materials to our factory for recycling.

Typical applications

HARDROCK® Multi-Fix (DD) roofing boards are fully compatible for use with the followin roofing systems.

• Fully bonded, partially bonded, mechanically fastened single ply membrane systems and 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 combines with Hardrock® Multi-Fix (DD) to offer enhanced acoustic performance for the very highest specifications.

ROCKWOOL Acoustic Infills are available as plain, tissue faced or melinex faced trapezoidal shaped perforated metal deck infills, used as part of the system to enhance acoustic absorption. 

Superior acoustics

ROCKWOOL has a unique in-house design capability to provide bespoke project specific rain noise calculations and can support with a comprehensive suite of absorption and sound attenuation test data.

The service will support cost effective project design and help meet the Education acoustic requirements, BB93.

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