Chalky Limestone Coping

[daytonflyer53]

Our pool project was completed last fall and all turned our great except the chronic chalky appearance of our limestone. It’s interesting because it is only occurring on the pool coping limestone and not on the landscape limestone coping. Our pool has a SWG and our builder asked us to monitor the condition until spring to see if it went away after some exposure to the elements. Unfortunately we haven’t seen a change in the chalky appearance over time for the better. I’m concerned that when the pool deck was prepped with a muriatic acid wash before the concrete sealer was applied that it could have caused damage to the limestone which is creating the chalky appearance. Interested in others opinion.

 

[JamesW]

It looks like efflorescence.

When the cover is closed, you get moisture trapped beneath the cover and it soaks into the coping.

As the water escapes through the top of the coping, it carries minerals that are left as efflorescence.

The tile beneath the tracks will also begin to see efflorescence as the water cycles and picks up minerals.

Ground water will also increase the problem.

Try to manage the ground water and try to seal the coping including underneath as much as possible.

Try sanding a test spot to see if the efflorescence comes off without damaging the coping.

Use a good penetrating sealer.