By Kat Harrold
Photo - Jorg Breuning
Working with green roofs for quite some time we have come to appreciate the compatibility of the TPO waterproofing with the Electric Field Vector Mapping System (EFVM). Something important to consider however is the relation between the insulation and the waterproofing in determining the type of EFVM system.
A project using waterproofing adhered to the insulation requires a metal mesh EFVM system in between the waterproofing and insulation whereas the system that has the waterproofing mechanically fastened to the insulation requires only a wire perimeter on top of the waterproofing. Aside from being more labor intensive to install and modify, some roofing manufacturers would not warrantee their TPO with the metal grid between their waterproofing and insulation. Proceed with caution when roofers site incompatibilities with their TPO and an EFVM system. You may want to consider another manufacturer.