a mixture using our composition is in the range of about 30 to about 70 by weight as compared to the total amount of primary composition plus water the amount of water used is dependent upon the humidity of the environment and of the ingredients as well as the particular application we are unaware of the mechanisms or reactions which take place either within our composition itself or where our composition is mixed with water and sand or other aggregates but we do know that the results achieved are unexpected and significantly better than any other composition of which we are aware prior art underlayments for floors have many disadvantages and problems associated with them these problems include 1 they are relatively soft and have a relatively low and also inconsistent compressive strength 2 they are water permeable 3 upon drying a dusty surface is formed on them 4 upon exposure to adverse weathering they deteriorate or delaminate 5 their densities often do not meet requirements and 6 they cannot withstand relatively heavy weight there are many well known problems associated with conventional lightweight concrete including particularly its water absorptive nature which renders it susceptible to cracking and deterioration due to freeze thaw action also a relatively larger amount of such concrete is required to produce the same insulative effects produced by a lesser amount of our new composition in a typical use of our new composition for flooring the room in which the flooring will be installed has a conventional plywood subfloor the flooring underlayment mixture which has been mixed with conventional mixing means is pumped through a hose.