Abstract: An apparatus and method for controlling the production of foamed material in which the material and foam are delivered to a mixer (12) in predetermined relative proportions. The apparatus comprises a mixer (23) for mixing a foam solution and air together, and a foam generator (26) for conditioning the air and foam solution mixture and delivering the resultant foam to the mixer. The foam generator (26) comprises a plurality of foam generating chambers connected in parallel, valves (28) being provided to control the flow of air and foam solution mixture through each of the generator chambers. The volume flow rate at which foam is delivered to the mixer (12) is monitored, and the valves are controlled to direct the air and foam solution mixture through one or more of the generator chambers in dependence upon the volume flow rate such that the flow velocity of the air and foam solution mixture within the chamber or chambers is within predetermined limits.