Carlisle’s Sure-Flex PVC Walkway Roll is available in 80-mil and 110-mil thicknesses and is heat-weldable, and designed to protect PVC and KEE HP membranes in areas exposed to repetitive foot traffic and other hazards.Walkways must be installed at all traffic concentration points (i.e. roof hatches, access doors, rooftop ladders, etc.) regardless of traffic frequency. Walkways must also be installed if regular maintenance (once a month or more) is necessary to service rooftop equipment such as HVAC systems