As you can see, we have the radiant tubing installed below the rebar. We needed to keep it under the rebar and not passing through walls, since the GC is concerned the fasteners he is using for interior wall base plates could penetrate the tubing. If you enlarge this photo, you can see the 2' x 2' rebar grid, and the green paint outline of walls and rooms we chose not to heat. (Closets and Pantry). We used approximately 2100 ft of tubing, and over 1600 8" zip ties. We photo documented the installation for future reference purposes.