Which two materials are noted to be incompatible in roofing applications?

The pairing of PVC (Polyvinyl Chloride) and EPDM (Ethylene Propylene Diene Monomer) is known to be incompatible in roofing applications due to their differing chemical compositions and properties. PVC is a thermoplastic material while EPDM is a rubber-based membrane. When these two materials are used in conjunction, they can lead to issues such as poor adhesion and increased potential for leaks. This incompatibility arises because PVC can sometimes deteriorate EPDM, causing premature failure of the roofing system.

In roofing, it is essential to use materials that are chemically compatible to ensure the longevity and integrity of the roofing assembly. This choice helps maintain the effectiveness of seals and connections, ultimately preventing leaks and other performance issues.

Other material pairs mentioned, while they may have some concerns in specific contexts, do not demonstrate the same level of incompatibility as PVC and EPDM. Therefore, understanding the properties and compatibility of materials is key to successful roofing installations.