A product category that is gaining increasing importance: ROCKWOOL has introduced a new line of load-bearing mineral wool insulation for utility roofs. The development responds to changing requirements in flat roof construction, where roof surfaces are increasingly being used as parking decks, green recreational zones, or maintenance areas for photovoltaic and ventilation systems. For planners, this means that in addition to thermal properties, mechanical properties such as compressive strength and point load behavior according to DIN EN 826 and DIN EN 12430 are becoming increasingly relevant.
The new product line from ROCKWOOL is aimed at roofs in usage categories II to IV according to the flat roof guideline. While conventional stone wool insulation boards achieve compressive stresses of 30–50 kPa, load-bearing roofs or intensive green roofs require values of 60 kPa and upwards. The load-bearing variants are designed to meet these requirements while maintaining standard λ-values of 0.035 to 0.040 W/(m·K) – a balancing act achieved through adapted fiber structure and higher bulk density.
The market for load-bearing insulation materials is growing continuously, particularly in urban areas where land is scarce and roof surfaces are used for multiple purposes. Mineral wool-based solutions compete here with XPS systems (polystyrene rigid foam), which traditionally offer higher compressive strengths but are at a disadvantage in terms of fire protection (building material class A1 vs. B1). Especially for special buildings and buildings of building class 5 according to the model building code, this difference can be decisive for planning.
For processing, however, the higher bulk density also means a higher area weight, which must be taken into account in the static design of the roof structure. Moreover, load-bearing stone wool insulation boards typically cost 15–25 % more to purchase than standard versions – a factor that must be weighed against the savings from improved fire behavior and longer service life. The new product line underscores ROCKWOOL's strategic positioning in the growing segment of multifunctional flat roof systems and is likely to intensify competition with providers such as ISOVER.
