Abstract: This invention provides a re-usable, unitary, portable, lightweight decking form for the construction of modular housing units having a monolithic slab roof. The portable decking form comprises a relatively flat plate supported by a gridlike network of structural support members, interconnected in a manner so as to form a level upward surface. Connected to the gridlike network are two sets of ground-engaging means: a first ground-engaging support means including rolling means for rendering portable the entire decking form; and a second ground-engaging support means which includes vertically adjustable elevating means which can raise and lower the decking form between a first lower position where the decking form is supported by the first ground-engaging support means and a second raised position where the gridlike network is supported by the second ground-engaging means in a stationary manner.