The present invention concerns a method of producing an insulation product comprising a board of porous insulation material wrapped in a gas-impermeable foil, said method comprising the steps of providing a succession of porous insulation material boards on a first conveyor apparatus and feeding the boards on a second conveyor apparatus; providing wrapping foil and wrapping said foil to form a tube around the boards on said second conveyor apparatus, flushing the boards with an insulating gas, and sealing the wrapping foil at the ends of each board transverse to the direction of travel of the second conveyor apparatus.