I need to attach it vertically to some thick hard rubber roofing. There is a small section of roof which should probably normally have a parapit but instead the roofing rubber is not backed by anything. Then below it is a wood panel. So when it rains sideways the water runs down the roofing rubber and behind the wood panel.
I just need a piece of shingle to divert water to the exterior side of the panel. Roofing glues are made to never cure. Probably rightfully so, but that probably wouldn’t work to attach a shingle vertically as gravity would over power that tar-like never fully dry stuff. I tried construction adhesive & it didn’t hold.
Without seeing it, the best solution I can think of is to try cleaning it up real good with something like Simple Green(works amazing on rubber). After it's nice and dry, use some Eternabond RoofSeal tape making sure to have at least two inches overlap. That stuff will stick well to clean rubber and hold good for a few more years. Nothing will ever be a permanent solution until you can replace the whole piece of rubber roofing unfortunately .
I don’t have anything specialized like simple green, but wouldn’t acetone or denatured alcohol make a decent primer? I think priming the smooth rubber surface should be the easy part but it’s the bitumen band that’s tricky. It has a sandy texture and sand crumbles off when I rub it. Perhaps I should steel brush it where it needs adhesive.
This is a use case for a step flashing or pan. Use sheet metal cut to shape and bent at a right ( or other angle) to give you a nailing surface. You nail it to the roof deck and it stands up.
Thanks for the suggestion but in my case there is nothing to nail to. A shingle must be attached to thick (~2mm) rubber that’s just formed to be vertical. Perhaps I need to rivet the two rubber pieces together. Or I might try construction glue again but also get a couple metal plates and screws to clamp them together as a permanent clamp.