I have a 50s triplex near the beach with cathedral ceilings of tongue and groove, topped by 3/4 inch plywood and torch applied modified bitamen (asphalt) roof. That's it... No insulation, no attic. I'm told 2 options by roofers, apply Title 21 white reflective coating, or rip off the roof and start all over again adding insulation. The middle unit is especially hot as there is no cross breeze; there are skylights, double pane acrylic which don't help and don't open. Any suggestions....