A layer has a base material made from non-woven material the base material being made from fibres and has first pores formed by the fibres wherein the base material is at least partly filled with particles, rte particles at least partly filling the first pores and forming regions filled with particles. According to the invention, a layer may be designed and improved such as to present a high porosity and high temperature stability on an economical production with low thickness being characterised in that the particles create second pores in the filled state, the mean diameter of the particles being larger than the mean pore size of the majority of the second pores.