In reply to Big Mountain Man:
Berghaus once repaired an old waterproof for me, but I don't know if they'd still do that. Mountain Equipment said they would fix the zip on a jacket of theirs I had, but only if I had proof of purchase, which I didn't. The Seam Grip is much easier, and just as effective as a professional repair, although it probably won't look as good. I've successfully used it to repair waterproof jackets and overtrousers, gaiters, an Ortlieb map case and a giant inflatable trampoline.