::: Thumbs ::: Next >> ::: This is the design specified for us by WA9S. This is roughly $2500 worth of rebar and mat, in two layers, imbedded in what will be an 8 inch thick pour. This yields a ceiling that self-supports across a 17 foot span, with an allowable floor loading of 75 pounds per square foot. The supplier thought I was nuts when I asked for 16 mm bars, but he took my money and supplied them.