Abstract: The invention provides foam forming methods that comprise: (a) preparing a foamable system comprising at least one hydrohaloolefin; and (b) ensuring either (i) the substantial absence of long-term decomposition-inducing contact between said hydrofluoroolefin and an amine-containing catalyst; (ii) that an effective amount of surfactant is available in the system under conditions which prevent long term exposure of the surfactant to a long-term decomposition reaction environment; or (iii) a combination of (i) and (ii). Related methods, foamable systems and foams are also disclosed. Preferred embodiments provide polyurethane and polyisocyanurate foams and methods for the preparation thereof, including closed-celled, polyurethane and polyisocyanurate foams and methods for their preparation. The preferred foams are characterized by a fine uniform cell structure and little or no foam collapse.