Method for simultaneous and continuous foaming of two or more panels, each panel being provided with a pair of external layers of web material between which an intermediate layer of expanded polyurethane or phenolic material is interposed, comprising the steps of: i. advancing through a foaming station a plurality of pairs of continuous web material (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f) arranged mutually alongside, each pair comprising two web materials, which are the precursors of respective external layers, spaced apart from one another to define opposite surfaces of a respective panel of said two or more panels; ii. dispensing simultaneously a plurality of distinct flows of polyurethane or phenolic mixture, each for a respective pair of web material (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f), each flow being dispensed into a zone interposed between the web materials of the respective pair and containing below the polyurethane or phenolic mixture, while allowing the polyurethane or phenolic mixture to expand upwards; iii. wherein, during advancing in said foaming station, the web materials (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f) of each pair lie on respective vertical planes (V1, V2, V3, V4) and move along a horizontal advance direction, iv. distributing the thrusts exerted by the expanding polyurethane or phenolic mixture transversely to said advance direction by means of intermediate guiding and resting surfaces (13, 14, 15, 29) extending along said horizontal advance direction; v. contrasting the thrusts exerted by the expanding polyurethane or phenolic mixture transversely to said advance direction by means of guiding and resting surfaces (10, 30) of two parallel conveying devices that are movable along said horizontal advance direction, each conveying device being moved by respective rotating return driving means located at opposite ends. i. advancing through a foaming station a plurality of pairs of continuous web material (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f) arranged mutually alongside, each pair comprising two web materials, which are the precursors of respective external layers, spaced apart from one another to define opposite surfaces of a respective panel of said two or more panels; ii. dispensing simultaneously a plurality of distinct flows of polyurethane or phenolic mixture, each for a respective pair of web material (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f), each flow being dispensed into a zone interposed between the web materials of the respective pair and containing below the polyurethane or phenolic mixture, while allowing the polyurethane or phenolic mixture to expand upwards; iii. wherein, during advancing in said foaming station, the web materials (7; 7a, 7b, 7c, 7d; 7e, 7m, 7n; 7f) of each pair lie on respective vertical planes (V1, V2, V3, V4) and move along a horizontal advance direction, iv. distributing the thrusts exerted by the expanding polyurethane or phenolic mixture transversely to said advance direction by means of intermediate guiding and resting surfaces (13, 14, 15, 29) extending along said horizontal advance direction; v. contrasting the thrusts exerted by the expanding polyurethane or phenolic mixture transversely to said advance direction by means of guiding and resting surfaces (10, 30) of two parallel conveying devices that are movable along said horizontal advance direction, each conveying device being moved by respective rotating return driving means located at opposite ends.