The invention relates to a method for the production of a silicate foam of lower density, which comprises the following steps: (a) partial saponification of an aqueous dispersion of SiO2 particulates which have an average particle diameter ranging from 1 to 100 nm, with a strong base; (b) addition of a surfactant and a blowing agent, and dispersion of the blowing agent at temperatures below 50°C; (c) foaming of the mixture by heating to a temperature ranging from 35° to 100°C or by relieving the pressure; (d) stabilization of the foam obtained in step (c) with a curing agent; (e) sintering of the foam at a temperature above 500°C.