Metal Roof E-Curb penetration seals replace old-style rubber boots with versatile, precast components and non-sag 1-Part polyether sealants for installations on a sloped substrate. Chem Link’s Metal Roof E-Curb System can usually be installed in under 15 minutes and never requires flashing or mechanical attachment. E-Curbs are designed for use on metal roofing systems that require adhesion to Kynar 500® PVDF coated metals. E-Curbs are highly versatile for sealing penetrations around HVAC, mechanical, solar panel mounts, electrical, and any type of structural supports. TPO Primer is required for use with TPO single-ply roofing membrane.