Soudafoam SMX is an isocyanate free fixing foam. Soudafoam SMX is a moisture-curing system and performs best on moderately wetted porous surfaces (a.o. wood, concrete, stone). On non-porous surfaces, the best performance is achieved when the surface is approximately dry and when the joint/cavity is not deep (max. 7.5 cm). In the case of a deeper joint/cavity, it is better to fill the gap in two sessions, with a drying/curing time in between.