Yes. Provided that the joists are 12" off center and leveled with a laser level and the frame is sturdy, you can install the tiles over the joists. Your only limitation is the direction of the tiles; they must be installed perpendicular to the joists. Pedestal systems can be installed under the frame to even out any slanting or grade of the surface if working with a sloped roof deck. If you would like to lay patterned tiles you may by adding a surface 2 x 6 pressure treated spaced out every inch or so overt he surface. Lay tghe tiles on top as you final surface and you have a hardwood deck that will last a lifetime.