Can ZMesh be installed in an existing roof without a full replacement?

Yes, with roofing contractor involvement. Installing ZMesh in an existing roof requires removing shingles along the eaves and up valleys where ice dams typically form, laying ZMesh on the sub-roof with a layer of ice-and-water shield over the top, then relaying the shingles. While this involves labor, it is less disruptive than a full re-roof and results in a permanent, invisible system. ZMesh is particularly well suited to installation during planned re-roofing projects, eliminating the need for future disruption.