Roof repair and renewal

ScottnSherrie wrote:
As far as the patch goes, I'm afraid you won't know where the supports are until you start hacking into it. A stud finder may help but can't say for sure. Be aware the area to patch may have wiring so dismantle carefully.

I like the look the Webseal variant of Eternabond gave given that I did recoat the entire roof. I think the vinyl backed product would be easier where the roof is sound but the edge seams are the problem area.

I'm new to this, and I know different manufacturers will be slightly different, but can you give me some idea of how the roof is likely to be constructed? I'm assuming rubber on top of plywood, how thick is the plywood typically? Then some kind of horizontal beams that the plywood is fastened to? Plywood screwed down? Is there some kind of foam in there somewhere, like between the beams?

My thought is, if the plywood is screwed down then I should be able to cut away a square of rubber bigger than the soft area, use the screws to locate the structure underneath, cut away the plywood along the centerline of the structure where the screws were, then patch in a piece. If there's any open space under the plywood I thought another alternative would be to cut away the plywood in between the structure and then use plywood doublers underneath to support the patch.

I don't know if I'm explaining that well enough, but does any of it make sense? I'm still not convinced I can't just Eternabond and Liquid Roof over what's there and leave it be.