vermiculite/cement 5:1 question

[KEmerson]

Sorry if this one is old. I can't find it.
I keep reading about mixing vermiculite or perlite with cement at 5:1. What are we measuring? 5 what to 1 what?
Thanks

[Neil2]

By volume.

For example, five shovel fulls of perlite and one shovel full of cement.

And just enough water to make it "workable".

[Roadkyng]

mixing of materials is always assumed by volume unless otherwise specified, such as by weight

[KEmerson]

so for example if I know it took so many bags of cement to make my structure slab, I can just sort of estimate how many bags it takes to make a slab of a certain size and apply that to the verm/cement mixture? So if I want to replicate the area of the slab, all I have to do is replace some of the cement with the vermiculite for the same total?
Thanks
Kim

[dmun]

For all practical purposes the volume of the vermiculite (say, a four cubic foot bag) will be the volume of your vermiculite concrete. The portland doesn't take up that much room.

[KEmerson]

Thanks. Very helpful. How did we ever get by before the Internet?
Kim

[DimTex]

Before the internet I think we ordered out for pizza.

I poured my insulating layer last Friday and found for the 36 inch oven it took all of 3 four cu. ft. bags of Perlite to fill my forms to the 4 inch level.

[KEmerson]

I'm finding it won't take much too. Maybe four or five - tops. And I think $8.75/ 4c.f. bag is probably reasonable.
Thanks