Abstract: An improved fire retardant insulation material for buildings is disclosed. The insulation material comprises a mixture of perlite and natural or synthetic zeolite bound together by a lime-cement mixture. The insulation is reinforced by a three dimensional inorganic fiber network which bonds with the other materials to form exceptionally stable insulation materials. Natural volcanic rock may also be added to the lime cement binder as a replacement for a part of the perlite/zeolite mixture.