Managed to squeeze in three hours today. Finished plumbing vent removal, ladder loosening, and one sidewall termination bar / gutter removal. With one side loose, I decided to go ahead and remove the TPO membrane. I simply cut it along the front & rear ends and down the passenger side. Will have to complete that removal next time. Wanted to see how bad the roof is & begin to think about next steps. Some areas were pretty wet. That old-style TPO with the fabric backing is bad stuff.
Photos are below... (note: the white stuff on the roof is TPO backing-fuzz, not mildew)
- wall & roof framing is box aluminum (good! so glad it's not wood...)
- there is white hard foam insulation in the spaces between the rafters
- the luan ply roof appears to have been glued to the rafters and the foam too.
- the luan is not all bad, but there are bad areas in many spots, especially along the roof edge. The roof has a bit of a valley just before the side, so water doesn't run off very well.
- with the luan being glued down, I don't see how it's feasible to remove sections where the wood is still solid. I think the demolition would be hellacious and would tear up all of that foam, making the project a magnitude or three bigger.
- there's an aluminum 90 deg. corner strip that overlaps the luan and the fiberglass sides. That strip was pneumatically stapled on with really heavy staples (into the aluminum box framing. There are more staples than grains of sand on a beach. Removing it would be the absolute last option.
Solutions: (YOUR INPUT / ADVICE WELCOME!)
The most practical approach I can think of is to cut out the rotten sections (straight cuts in the closest solid wood) with a circular saw set very shallow. Pull out all the bad wood, chipping it out from under that corner angle. Cut new luan sections to fit and re-glue it in place, tucking it under the corner angles as best I can. I would make the sections as contiguous as possible to maximize strength, though obviously this approach will result in more joints in places away from rafters.
What kind of glue would I use? Liquid nails? I think I'd like something that set up a bit faster...
I could consider overlaying the entire roof with another layer of luan for added strength, but I'm not sure it's necessary. The roof feels pretty strong as-is. And of course it's a lot more work. Also, it would have to rest on top of that corner angle along the sides, though I could sand / round the edge prior to putting the new TPO on.