Temperature differences in material, heat expansion and contraction shrinkage of edges with cooling downwards. Mugnaini commercial ovens utilize perlite concrete placed on top of the insulating blanket and topped with loose-fill as an extra. Between the two methods, the perlite insulation blanket then cement rendering is most effective in heat insulation, What is PERLITE and why do we. I would appreciate any advices/recommendations and i would also like to hear feedback from owners of similar VERMICULITE or PERLITE and PORTLAND CEMENT – Dry Mix 5 parts Vermiculite or Perlite - to - 1 part Portland Cement in a Mixing Tub or Wheelbarrow - (5 Gallons / Shovel - to - 1 Gallon / Shovel). Im ready to start building my very first wood fired pizza oven using gym ball, perlite, portland cement, cement enhancer, chicky mesh and firebricks for the base only. Ratio 5:2. Sep 28, 2017. It’s really light but a great insulator and so our insulation layer is made by mixing 5 parts perlite to 1 part cement. Hello everybody. You can get a 100 litre bag for less than £20 on Amazon which is great value. For a 5 to 1 ratio of perlite to cement you will mix in about 2.4 cubic feet of cement. Re: perlite -portland mixture for oven floor 84"= 7 feet 72"= 6 feet 5"= .42 of a foot 7'x6'x.42'= 17.64 cubic ft You have 12 cubic feet of perlite. How to make heat resistant concrete type for buildig wood fired pizza ovens and similar applications where heat and heating is present. Refractory concrete mixture ingredients recipe for mixing by hand and concrete in building pizza ovens. What is the best perlite/portland cement ratio? From Pinkbird. Manually mix the perlite together with the cement so there is no white left and then add a little water to bind it all together. Heat differences in materials. Perlite render pizza oven. Add just enough water to get the entire blend wet as you mix with a shovel or hoe (hoes are good for this process). « on: February 01, 2014, 06:02:45 PM » As I have been on this forum, I have seen many ratios of perlcrete - from 6:1 to 10:1. 12+2.4=14.4 And usually the wet mix has a lower volume than the dry ingredients.