The hearth is 2 inches high. Natural stone slate tile, really Quartzite on ½" Durock cement board all on ½" Micore 300 as a base for the hearth. "Combustible flooring must be protected with a covering of noncombustible material with an R-value of 1.2" is needed for the 2004 HearthStone Heritage hearth. Talk to your building inspector and see what he wants to see, them a architect or carpenter to see how to do it, I guess. The total weight loads are high on a stove and hearth. Expert help planing is the only safe way to go. Start a Question in The Hearth Room forum those guys have some ideas. The stove back is 10 inches to the centre of the connector T vertical vent.