Product description


  • Allow continuous ventilation and drainage behind cladding
  • Up to 120 minutes fire integrity
  • Tested to ASFP ‘Fire Resistance Test of Open State Cavity Barriers’ utilising BS EN 1363-1 and Principles of BS EN 1366-4
  • Suitable for horizontal (open void) and vertical (full seal) applications
  • Third-party approved
  • All horizontal cavity barriers are colour-coded for ease of identification


SIDERISE 'Open State' cavity barriers represent the default choice for market leading, high performance, ‘Rainscreen Cladding Cavity Barrier’ applications.

Used in the external envelope or fabric of buildings, they ensure the system will drain freely, whilst maintaining airflow and providing an effective hot smoke and fire seal.


SIDERISE RH 'Open State' horizontal cavity barriers

Incorporates a continuous bonded intumescent strip to the leading edge and encapsulated in a weather resistant polymer film. In the event of exposure to fire, this expands and fully seals the designed ventilation gap formed at the time of installation between barrier and the rear of the cladding, in compliance with CWCT and NHBC guidance for air gaps up to 50mm.

The range of cavity barriers are colour-coded for ease of identification.


SIDERISE RV vertical cavity barriers

Are specifically intended to full fill the void. As a full fill barrier system, the integral intumescent strip is not required. This product is available with a factory applied DPC pre-bonded to the surface if required.

Note: This product was previously known as Lamatherm CW-RS cavity barriers for rainscreen cladding.

SIDERISE® RH / RV are the first ewcl5 certified cavity barriers for open state ‘rainscreen’ facades.


Watch the SIDERISE RH & RV installation guidance video.