Hi everyone, I have a question about the ratio of vermiculite to portland cement that will be poured on top of the hearth. The forno bravo site recommends 5 parts Vermiculite to 1 part Portland cement. Does this ratio go by weight or simply by volume? For instance for every 1lbs of cement do I have to weigh 5 lbs of vermiculte, or does it mean for ever bag of cement, I simply refill the empty cement bag 5 times with vermiculite and mix that? I assume it's by weight but that would mean a hell of a lot of vermiculite!

I'm planning to build my vermiculite layer 68 inches long by 65 inches wide by 3.5 inches high. How much vermiculite and cement would that represent?

Can someone help me with this?

I'm planning to build my vermiculite layer 68 inches long by 65 inches wide by 3.5 inches high. How much vermiculite and cement would that represent?

Can someone help me with this?

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