TFP has been a boon for my nice clear water for several years, and especially for figuring out what was in my pool house when I moved in and the previous owner had little idea what was going on.
I have a 40x20 kidneyish shaped inground pool with metal sides. I believe about 20-25 years old. Several years ago I noticed the coping? seemed to have a larger gap at one location and it got about 1/2 mm bigger every year? When I ran my finger over the liner below this, it seemed like a crack had formed in the metal side of the pool? I actually had a pool constructor out, who told me it was fine, nothing to worry about, but that fixing it would require replacing the pool, >$50k. Photos of the gap:
photos.app.goo.gl
photos.app.goo.gl
I suspect the problem is that when it freezes each winter, the ice expands the pool (and the crack) slightly, even though I drain about 2.5-3 feet off when winterizing in the fall, but it refills about 1.5-2 feet with snow and rain during the winter.
However, the crack has continued to widen each year and must be stretching the liner. The crack is perfectly vertical and seems like a failed weld? Feeling it through the liner, it feels like it's now about 5 mm (1/4")? Now when I feel around it, I feel some dirt between the liner and the steel. Looking carefully in the pics above, I think you can see a bit of the bulging in of the liner due to the dirt. Incredibly, the liner seems to be holding fine with no leaks. Here is a cross sectional diagram of what I think I feel:
photos.app.goo.gl
I suspect this can't go on forever without failure? Questions:
I have a 40x20 kidneyish shaped inground pool with metal sides. I believe about 20-25 years old. Several years ago I noticed the coping? seemed to have a larger gap at one location and it got about 1/2 mm bigger every year? When I ran my finger over the liner below this, it seemed like a crack had formed in the metal side of the pool? I actually had a pool constructor out, who told me it was fine, nothing to worry about, but that fixing it would require replacing the pool, >$50k. Photos of the gap:
New item by Tim Turkstra
photos.app.goo.gl
New item by Tim Turkstra
photos.app.goo.gl
However, the crack has continued to widen each year and must be stretching the liner. The crack is perfectly vertical and seems like a failed weld? Feeling it through the liner, it feels like it's now about 5 mm (1/4")? Now when I feel around it, I feel some dirt between the liner and the steel. Looking carefully in the pics above, I think you can see a bit of the bulging in of the liner due to the dirt. Incredibly, the liner seems to be holding fine with no leaks. Here is a cross sectional diagram of what I think I feel:
New item by Tim Turkstra
photos.app.goo.gl
I suspect this can't go on forever without failure? Questions:
- Is there a good/known way to repair this? Ironically, I just poured a new deck over this section last year.
- How do I disconnect the liner from the pool wall at the top so I can see what's going on and post a picture of this?
- When I lower the water level this fall, I plan to disconnect the liner at the top and vacuum out the dirt that's between the liner and the pool wall?
- All I can think of is pulling the liner away from the metal wall and trying to have the metal welded. (I don't weld.)
- Or I could I drill small holes in each side of the metal and lace it together with UHMwPE fibre (Dyneema, much stronger than steel). I'd use 1.6 mm (1/16") with a break strength > 500 lb, which might stretch ever so slightly but hopefully pull back every spring when the ice melts? However, UHMwPE fibre stretches very little; stretch would be in the lacing geometry. 1/16" holes spaced 3/16" laced would hold > 64,000 lbs/linear foot (32 tons/linear foot), which sounds pretty strong to me, but that's a couple hundred holes to drill! (7/64" is 1600 lb line strength, but then I'd have to drill 1/8" holes... and 1/8" lacing under the liner) What I don't like would be the sharp edges of the holes on the UHMwPE fibre. I could round them on the inside, but not the other side.
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