9” ZMesh is sandwiched in between two layers of ice and water shield and stapled to the roof decking. Shingles are then secured with nails directly on top. Nails can pierce the ZMesh as long as the nails do not come in contact with any other metal objects. The ZMesh comes in 9” wide rolls and is rolled out over the area to be heated. Heating at least 6” above the roof eaves is recommended.