Why not? It is not intended that the roof itself support the mast, though we have all seen examples where this was the case.
Look at your PoCo regs. I am certain that they will want the mast supported by anchors into the wall, or even all the way through the wall and into a backing plate. This is a detail not often obeyed.
Likewise, the PoCo standard will set limits on the height a mast can extend above the roof, and what sort of bracing is expected. Please note that guy wires are not often allowed.
Most PoCo standards are availabe, on line and free, at their web site.