Rock Mineral Wool - Rocksilk Krimpact Flat Roof Slab Extra


Flat roof


Rock Mineral Wool


Rocksilk Krimpact Flat Roof Slabs are  high performance, non-combustible Rock Mineral Wool slabs with high compressive strength, suitable for use on all types of roof deck, and can be overlaid either with a single ply membrane which is mechanically fixed, or with a waterproof membrane consisting of either a fully bonded built-up bitumen roofing system, or mastic asphalt.

Rocksilk Krimpact Flat Roof Slab Extra is manufactured with a higher density than Rocksilk Krimpact Flat Roof Slab Standard to provide a higher level of compressive strength for use in flat roofs requiring long term compression performance.

Slabs contain a special additive to ensure their water repellency.


  • Excellent thermal performance.
  • Non-combustible A1 Euroclass Reaction to Fire classification
  • Absorbant nature of the product reduces the drumming effect of rainwater
  • Manufactured using specialist Knauf Insulation Krimpact Technology for high levels of compressive strength and durability
  • The nature of Rock Mineral Wool allows slabs to knit together at joints
  • Dimensionally stable 
  • Compatible with a wide range of single ply membranes



Thickness (mm)Length (mm)Width (mm)Thermal Conductivity (W/mK)R-Value (M²K/W)Euroclass Reaction to Fire ClassificationFacingArea Per Pack (M²)Area per Pallet (M²)


BBA Certificate 08_4526 Rocksilk Krimpact Flat Roof Slab
Eurofins Gold
A1 Euroclass Fire Rating
CE Marking
Bureau Veritas
Green Guide Rating B-C