Abstract: An adjustable telescoping support mechanism is provided that may be connected between members of two positionally separated and supported truss members for providing support for a concrete-forming surface for fabricating building floors or ceilings. The telescoping support mechanism may be easily positioned adjacent to the location of vertical concrete structures of a building, such as building support columns, stairwells or elevator shafts in order to tie in a concrete floor or ceiling to the vertical concrete structure. The mechanism provides a means for fabricating a floor or ceiling adjacent to a vertical concrete structure either prior to or after the vertical structure has been fabricated, without the need for supporting scaffolding, which impedes normal construction activity and creates safety issues.