Bending back the corners will tend to flatten the wire perfectly. Lay out the pattern of radiant tubing and tie it to the mesh. Run the tubing from each zone up into the manifold. Pour the concrete. This should be 4-6 inches deep.
Propane is the backup heating source.
Thermosiphoning tips 1. Use thermosiphon only in areas where freezing temperatures are rare. Cold pipe from bottom of tank to bottom of heat source should slope down so as not to trap air. Use a tee off the tank drain as the cold pipe returning to collector so all the tank water is heated. Hot pipe should slope up from top of heat source to to up the side of the tank to allow room for heat and air bubbles to rise in tank.