Product description

Rainscreen cladding is a widely specified finish for many high rise buildings, facilitating creative and aesthetic designs. But balancing the breathability of these constructions with effective fire protection can be a challenge. To help overcome this, ROCKWOOL SP Firestop VRB has been specifically designed to form an effective open-state cavity fire barrier.


ROCKWOOL SP Firestop VRB provides essential fire resistance for external cladding systems and forms an important part of the comprehensive range of ROCKWOOL’s fire protection products. Designed to allow for ventilation and drainage of the cavity under service conditions, it has been rigorously tested with ROCKWOOL RAINSCREEN DUO-SLAB to ASFP TGD 19. It ensures that moisture is allowed to escape from within the façade system whilst maintaining adequate airflow. The important combination of non-combustible mineral wool insulation and an effective intumescent strip supports the design of safe façade systems and, when combined with RAINSCREEN DUO SLAB, works to prevent fire risk in tall buildings above 18m. SP Firestop VRB has been developed for use as an ‘Open State’ cavity barrier for drained and ventilated rainscreen systems. The Firestop allows moisture to drain from within the façade system whilst ensuring the flow of air. In the event of a fire the Firestop will react to create an effective smoke and fire seal.



Fully tested to ASFP TGD 19


  • Highly responsive - in the event of a fire the firestop will react effectively to create an essential smoke and fire seal.
  • Fire integrity – it ticks the right boxes by satisfying the NHBC and CWCT guidance for ventilation gaps at fire barrier locations, offering 60 minutes fire integrity.
  • Industry proven – the product is fully tested to ASFP TGD 19: “Fire resistance test for ‘open-state’ cavity barriers used in the external envelope or fabric of buildings”, ensuring complete compliance on a build.
  • Weather resistant – SP Firestop VRB is ideal for exposed buildings as it comprises of a stone wool barrier with a continuous intumescent strip to its leading edge, encapsulated by a polythene sleeve to keep moisture out.
  • Easy site storage and handling - installed horizontally and designed to ensure an appropriate open air space is maintained, the SP Firestop VRB is suitable for cavity widths up to 300mm.
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