Hair-line Crack

[Swimming Hole]

In-ground plaster pool. Appx 28000 gal. Halfway between deep and shallow end is a bench seat, about 10’ long and 18” below full mark. I have a vertical crack from the corner of that bench seat down to the bottom of the pool, approximately 7’ long. It is a HAIR-LINE crack that does not extend up into the tile line. The “bucket-leak” test shows no water loss to leaks. Plaster is 9 years old but still looks great. No evidence of cracks in the decking and no separation in any seams. When I say hair-line, I mean if I drew a fine point pen line next to it I believe the pen line would be wider. I should also mention it goes down about 3’, then stops for about 18”, then down another 3’ or so. (Looking down through water so may be different when drained.

So, what do you all think? Surface crack in the plaster? Does this happen? Or, a structural failure and needs to be torn apart and fixed? TIA.

 

[AQUA~HOLICS]

Surface Cracks usually don’t appear in older plaster unless there is movement in the plaster/ Shotcrete. I would document the start and finish of the cracks and see if they are getting longer. You can use a dye to see if it gets sucked into the crack at all and see if it’s loosing the smallest amount of water that a bucket test would not indicate.

 

[Swimming Hole]

Surface Cracks usually don’t appear in older plaster unless there is movement in the plaster/ Shotcrete. I would document the start and finish of the cracks and see if they are getting longer. You can use a dye to see if it gets sucked into the crack at all and see if it’s loosing the smallest amount of water that a bucket test would not indicate.

Thanks for the reply. I have been watching it for a little over 3 months. Although I did not mark the ends, I can say it does not look like it has changed/grown at all. Too cold to get in the water to mark/dye test right now.