To obtain a light and compact insulating screed (even on uneven surfaces where it would be impossible to lay rigid panels) mix Suberglass made of granular cork and natural sodium silicate in the following proportions:
Suberglass 70: at 1 cubic meter of Ri-cork 3-14mm add 70kg of sodium silicate (8 bags of cork with 2 tanks of sodium silicate)
Suberglass 90: at 1 cubic meter of Ri-cork 3-8mm add 90 / 100kg of sodium silicate (3 silicate tanks with 9 bags of cork)