I'm looking to install an Englander nc13, and I'm new to wood stoves (at least the install part). I can figure out the pad size just fine but the r-value has me worried. The instructions specify an r-value of 2.0. The highest r-value product I can find locally is Durock Next Gen 1/2" at 0.39. To get to the minimum of r-2 I would need to stack basically 6 sheets up. I live in a mobile home so I would like to have a higher r-value without using 350 pounds of durock under my 300 pound stove. According to the hearth.com article on hearth pads 1” ventilated airspace has an r-value of 1.43. Obviously I can't use 1x2's to do this because they are combustible. And I have seen that some people are using metal studs, but I was thinking that they have a high conductivity for heat. I was thinking of using durock itself for the spacing... cutting 1" strips and stacking them 2 high and spacing them 12" on center. I'm wondering if anyone has tried this or if anyone thinks this is a good or bad Idea. The picture shows basically what I'm thinking of. The top isometric shows it with a sheet of sheet rock under it which would need to have the paper removed from the top to have it count as r-value but even with out counting it there would still be and r-value of 4+. Neither top or bottom calculation includes tile or thin set. Is my logic wrong or would this work? Does anyone have any other ideas? I don't want my family to become a satistic! The rest of the install should be pretty easy... minimum clearances plus, double wall stove pipe, Supervent chimney, oustide air... Following the instructions should be easy since I'm a pro carpenter but the hearth pad is the only worrisome part.