Abstract: A method and apparatus for vertically molding concrete slabs in which a tilted semi-cubical enclosure is provided containing a plurality of plates spacedly positioned from one another such that a cavity is formed between plates in which the slabs are formed. The tilt of the enclosure maintains the plates and spacers in their desired positions during loading and unloading of the enclosure. Within one aspect of this invention the spaced plates are insulation plates having fasteners projecting therefrom into cavities such that when concrete is poured into and permitted to harden in the cavities, the insulation plates will be laminated to the concrete.