Abstract: The invention relates to a panel with a porous shell and a spring layer, part of which enters the shell and produces an integrated sealed barrier. The foam of the shell is an integral skinned foam and the shell has a core with a substantially homogenous density and a porous skin. The overall density of the shell is between 150 and 350 kg/m3. The skin thickness is between 0.3 and 2 mm and has a permeability such that a 2 mm thick foam strip cut into the shell and integrating the skin exhibits air flow resistance of between 250 and 2000 N.s.m?3.