A panel for a building form made of insulating material such as polystyrene is integrated with a reinforcing member for enabling the panel to resist deformation due to forces applied against its concrete-facing surface. Reinforcement of floor/roof panels is beneficial to reduce the amount of, or eliminate the need for, shoring for supporting the weight of wet concrete or workers. The reinforcement resists against deformation due to cracking, splitting etc. Reinforcement is likewise beneficial for wall forms where the weight of concrete asserts significant pressure against the concrete-facing surface of the form, in order to resist deformation of the wall forms under pressure. The reinforcing member may be made of a plastic material such as polypropylene or high-impact polystyrene. Methods of manufacturing reinforced form panels are disclosed.