Originally Posted by N'om'ad
I agree but I don't understand your suggestion - you'd run a bead along the edge of the patch?
To be clear, I'm suggesting using JUST seam sealer/adhesive - an 'all-in-one' product - to glue down AND seal the patch. A patch that would overlap the hole by at least an inch or two, meaning that there would be an inch or two of adhesive/seam sealer all around any hole and I'd make sure there was enough applied that it was squeezing out of all edges all around so a perimeter bead wouldn't be required.
I can't see that that would be any less solid than a welded patch and, even if it was, would easily last the 10-20 years (absolute max) that I want out of it
What I mean was that you'd take your adhesive and seal around the edge of the patch (to make a patch - glue - floor sandwich), then after that dries, you coat the seam with seam sealer. That way, you have two layers of sealant around the hole. If the glue fails, the seam sealer will still keep the water out.
You probably could find an all-in-one product that would work. Using two separate ones is probably technically overkill, but it's relatively cheap, so people do it anyway.