Lightweight wood-based sandwhich panel type board and process for producing it

Disclosed is a method for producing a sandwich type engineered wood panel. The board has an upper cover layer (410), a lower cover layer (420), and an intermediate layer (430) disposed between the upper and lower cover layers. The upper and lower cover layers and compacted, and the intermediate layer is foamed. Either no foaming of the intermediate layer occurs when compacting of the upper and lower cover layers begins, or the upper and lower cover layers are compacted before the intermediate layer is foamed.