Solid state venting valve for a fuel tank

The invention relates to a valve apparatus for use in the interior of a fuel tank, said valve apparatus comprising a substantially flat housing (2) defining a channel (7) between an inlet orifice and an outlet orifice, and a membrane (1) arranged to seal said channel, wherein said membrane (1) is adapted to be impermeable to liquid fuel and permeable to fuel vapor. The invention also relates to a fuel tank comprising such a valve apparatus and to a motor vehicle comprising such a fuel tank.