Michael Collins applies a 1/2" Rub-R-Slate roof plaster over the papercrete-recycled carpet base roof. Rub-R-Slate is similar to basic papercrete, with asphalt emulsion added. This speicific mix was paperpulp, water, hudrated lime, kaolin clay and emulsion only, no cement was added. To learn more visit www.dirtcheapbuilder.com