What is considered normal aging for plaster? What are most important things for plaster longevity?


Oct 26, 2019
When I purchased my current home I inherited a kidney bean shaped pool that was built in the 70's with a cracked beam, some loose tiles and coping and old plaster. I did the coping and tile first but held off on the plaster and then after 10 years in the home I did a full renovation including new decking, tile coping, electrical work and new plaster. The pool is in it's 9th season since renovation and is in pretty good shape.

I have continued to become better at understanding the nuances of balancing my chemistry and what is important to protect the pool and equipment but this is my first experience watching plaster through it's full lifecycle.

What are considered normal signs of aging plaster? The pool has some light spots that are a little rougher than others but do not flake easily if you inspect them with you fingers. In general the surface is still smooth and flat in most places. The polaris has rubbed a few spots more than others...

My main question is what can you expect in 10 year old plaster? Is some light spot etching normal?

My other question is what factors and practices are most important in protecting the life of pool plaster?

FYI, I have become increasingly aware of the importance of calcium in regards to protecting pool plaster. I use calcium hypochlorite shock and live in an area with pretty hard water so my levels have never been low and by closing the levels are probably somewhere between 250 and 300. I always have made sure my alkalinity and ph are good before closing but never paid that much attention to calcium until the year where I discovered the importance of the LSI. I live in MD btw. We can get cold spells here but the winters are not too bad. We have some winters where we get no freezing at all.



Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
As you have figured out it is not any one chemical but aggressive water at CSI less then -0.6 that erodes plaster. pH and CH are factors that keep water from becoming aggressive.

A lot of the setup for plaster longevity happens at the installation and startup.

More at Plaster Installation and Maintenance - Further Reading

Plaster can get messed up due to improper acid washing or rebar rust stains coming to the surface.

Some things are under your control and many are not.