Methods for preparing polyurethane flexible foam are described, wherein an organic polyisocyanate is reacted with an active hydrogen-containing component such as an organic polyol, in the presence of a urethane catalyst, a blowing agent, optionally a cell opener, and a siloxane-based surfactant composition as a stabilizer for the foam. The siloxane-based surfactant composition comprises a silanol-functionalized organosiloxane having general formula (I), wherein: the R groups are independently a C1-C3 alkyl, phenyl, or —OSi(R)3; provided that at least one R group is a hydroxyl (—OH) bonded directly to any silicon atom and X is an integer from 0-200.