I had that problem a few years ago. I'd bought a Blacks Goretex jacket (it's still in my garage) and the seam tape was the first thing that fell off. I visited a camping shop and they sold me a length of 1" wide stick-on tape, it kept my jacket going for another two years or so. The problem is I can't remember where I bought it and can't remember if it was just stick-on or iron on? Old age??? If you find such a product I'd go for it. One thing I do remember though is stripping out all of the old tape, which when measured was my guide of how much of a length to buy.