I have a few clients that appear to have a roll on pool plaster of some kind - both on identical 50+ year old pools. Both will need renovation shortly as the interior surface is failing and delaminating all over the place. The problem is that this plaster product looks like a roll on, not trowel on product and is less than 1/4" or so in thickness in many areas. Normally I would say that a sandblast is in order to get down to something solid in terms of substrate - but both clients say they had to sandblast last time the pool was renovated and neither are excited about paying for another round of sandblasting.

The surface now is about 5 years old and about 15% peeled and delaminated. Its too risky to go over with something else since I am sure this super-thin plaster layer is sure to continue to delaminate. Scraping will get off a bunch of old material, but not enough to avoid sandblasting in my opinion. Just looking for any feedback from contractors who use, or renovate pools with, roll on pool plasters. I am experienced with tile, plaster and paint finishes in concrete pools but not roll on plasters.