3 Sealant Types Used in the Installation of Metal Roofing and Siding Products

Non-Skinning/Non-Curing Butyl Sealant

These types of sealants are used purposely in metal roofing and siding applications because panel joints and laps create a very thin space between the materials that are subject to continual dynamic movements which will subject the sealant to shear force.  Only a non-skinning, non-curing sealant can perform under such extreme conditions as these types of sealant will never cure or harden over the life of the roof or siding. Butyl sealants should only be used where dynamic movement of the material will take place due to thermal expansion and contraction and are not subjected to exposure to Ultraviolet light. UV light will break down these types of sealants overtime making them impractical in exposed applications.

Extruded Butyl Tape

These types of sealants are used in a similar fashion to Non-skinning/Non-Curing sealants as butyl tape will never cure or harden over its lifetime. Butyl tape’s main use is for high infiltration areas such as under the joggle cleat at the eave or valley condition or in areas where a continuous aggressive bead of sealant is recommended such as used to seal the top and bottom of the zee closures on ridge or peak condition.

This group of sealants fall into two categories, Urethane and Siliconized.  These types of sealants require a specific mass of material, cures relatively hard, and will easily fail when subjected to shear and dynamic forces. AEP Span recommends urethane and siliconized sealant only for non-moving joinery and perimeter seals that are exposed to sunlight and require a curing UV resistant sealant.  It should be noted that although these sealants are recommended for use on AEP Span roof and wall products their use should be limited, as most of AEP Span details utilize concealed gun grade Non-skinning/Non-curing butyl sealants or butyl tape sealants in concealed applications.