Abstract: Substantially closed cell rigid polyurethane foam cores of laminates are disclosed which are scorch-free, have a density of 50 kg/m.sup.3 and are made using water as the sole or main blowing agent and without the need to use a CFC. The foams are prepared from polyol compositions comprising the product of alkoxylating an initiator having a functionality of more than 2, at least one aromatic ring and at least one amino nitrogen atom. The initiator is preferably a Mannich condensate of a phenolic compound, formaldehyde and ammonia or an alkanolamine and the polyol is preferably used together with a second polyol having a functionality (or average functionality) of at least 1 but less than 3 and a molecular weight M.sub.w (or average molecular weight) of 250 to 4000.