Abstract: In the production of slabstock polymeric foam, foam reactants are delivered to a vessel (1), the reacting foam mixture passes over an overflow outlet (2) from the vessel and along a downwardly inclined fall plate (3) to a conveyor (4), two separate covering layers, namely a lower flaccid plastics film (26) and an upper relatively stiff paper foil (28), are applied over the reacting foam mixture near the overflow outlet (36), a blanket (40) weighted by free floating plates (46) is positioned over the cover layers in the foam expansion zone to press down lightly on the foam. The separate plastics film and paper foil are provided by delaminating a composite sheet (21), and are delivered to the foam surface in substantially tension-free condition by a take-off mechanism (22) which draws the composite sheet from a supply roll. Improved economy is achieved as a result of improved characteristics at the top of the foam block produced.