disclosed are formulations adapted to form a foamed cementitious composition , the foamed cementitious composition itself , a method of forming a hydraulic binder foam , and a method of conveying and applying the resulting foam to a substrate . a pumpable cementitious slurry is formed , the slurry is mixed with a gas such as air , and is subjected to mechanically created turbulence to generate gas bubbles and create a foam , which preferably is stabilized by a foam stabilizing agent such as polyvinyl alcohol present in the slurry . the foam is then conveyed to a nozzle or other suitable dispense point from which it is applied , for example sprayed , preferably uniformly , onto a substrate to be coated . prior to dispensing , a set accelerator is preferably injected , which causes the foam to gel , which in turn improves the hangability of the product on a substrate . the spray material adheres to the substrate and hardens to form an insulative coating on the substrate . also disclosed are dry compositions comprising a hydratable cementitious binder , a mechanical foam stabilizing agent , and optionally a fibrous component , set retarder and air entraining agent , said composition providing , on the addition of water , gas and mechanical turbulence , a settable foam which is capable of spray application to a steel structural member and which , after spray application , is adherent to the member in the foamed state and after setting . the foam after setting , forms a fire and heat protective adherent coating on the member .