Some time ago, when I was in this situation, I put one of the Glen Martin roof top towers on the floor of my attic and had a roofing company put a roof jack in the roof just above the tower. I mounted the azimuth part of a Yaesu 5400 rotor on the shelf of the tower, ran the mast up through the thrust bearing and out through the roof jack, and put the elevation part of the rotor near the top of the mast. The mast was long enough so the antennas cleared the roof sufficiently. Around the mast just above the roof jack I placed an upside-down funnel-like shape of metal to divert any rain water away from the roof jack.

Ron W5RKN