What if the deck is located above a heated living space or roof?

Decks over a heated living space or roof present a secondary concern — meltwater from the deck can run down onto the roof beneath and refreeze, forming ice dams at the roof edge. Installing a roof deicing system on the roof below the deck — ZMesh for non-metal roofing or Tuff Cable in Invizimelt for metal roofing — ensures meltwater has a complete path off the building without backing up under the roof edge.