The properties of landfill gases are principally determined by the presence of methane and carbon dioxide and any air that these gases are mixed with. The migration of these gases, as a result of diffusion and pressure flow, have increased in recent years and present a risk to both health and safety in new and existing buildings. Radon enters buildings by airflow from the underlying ground. The two methods for sealing against Radon are the passive system, normally achieved by increasing the air tightness of the damp protection within the floors and walls, and an active system, which requires providing a powered radon extraction system by means of an integral fan. Landfill gas can enter buildings through gaps around service pipes, cracks in walls below ground and floor slabs, construction joints and cavity walls. In areas where significant concentration of radon is present, sufficient protection can be provided by a well installed damp-proof membrane linked to the damp proof course or sealed to a cavity tray system. Dwellings in areas where higher radon protection is required, should be supplemented by the provision of sub floor ventilation or depressurisation. 
 
SIGMA GPS GR DPC provides protection against the ingress of these gases when sealed to both the slab membrane and DPC or cavity tray system.  The use of factory welded preformed units, i.e. pipe penetrations, corners, stop ends and changes of level can be used as part of a gas protection scheme for either a passive or active system.  SIGMA GPS GR DPC conforms to the current requirements for use as part of a gas resistant membrane system.
 
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**None Returnable/Refundable once in Transit**
 
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**Isle of Wight and Scotland areas must be quoted - Email sales@straight2site.co.uk**