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Rockwool Rockfall Overlay Boards

Designed as a warm pitched roof thermal insulation system, Rockfall Overlay Boards are produced from stone wool with a high compressive strength to span and cover the rafters. The thermal performance of the roof can be further enhanced through the use of Rockwool Flexi slabs between the rafters The system is an effective way of providing an excellent thermal and acoustic performance for domestic, commercial and industrial buildings through the use of non-combustible insulation.

Rockwool Rockfall Overlay boards are CE and Key marked in accordance with BS EN 13162.

Non-combustible, achieving a classification of A1 in accordance with BS EN 13501-1.

Rockwool insulation products do not contain blowing agents with an ozone depletion potential (ODP) or global warming potential (GWP), are CFC-HCFC-HFC free and 97% recyclable. They will not react with metal components or cause loss of plasticiser from PVC cables and pipes.

General information
Uniclass 2015
Pr_25_57_06_56 Mineral wool slab insulationPrimary

K11/55 Rigid board insulation fixed as roof sarking

K11/695 Rigid board insulation fixed as roof sarking

Specification data - Mineral wool slab insulation
Product Reference

Rockwool Rockfall Overlay Boards


50 mm

60 mm

70 mm

Standard product features


2000 mm.


1200 mm.

Thermal conductivity (λ):

  • 0.035 W/mK – Underlay.
  • 0.038 W/mK – Overlay.

Fire rating:

To BS EN 13501, Class A1.


The incorporation of Rockfall in a roof can provide noise reduction of 40 dB or more, depending on construction details.

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