Pool floor has started to crack, what do I do now?

[Draddy]

Old 1960s pool, was refinished before I bought the house 3 years ago. We have been having trouble with this particular spot and staining. It often was visibly dirty, sometimes could be brushed away, sometimes couldn’t.

recently put in all new equipment and a SWCG which has helped keep the pool cleaner by running longer (vsp) and then of course consistent chlorine output.

this spot when it wouldn’t brush away, I did find that muriatic acid in one of those pole based surface applicators would remove the stain after ~30 seconds. Vitamin C either didn’t work or stained it more. This lead me to believe I have a rebar rust issue.

I’m not losing any measurable water now after an overnight test, but this is the first time I’ve noticed this to be an actual crack in the pool floor. The largest section appears to be 1/16th or so wide, and you can feel the crack with your toes.

the length of the crack appears to be around 14 inches long, but you can see a continued seam that hasn’t cracked yet.

What do I do now? How scared should I be? Is there a wet fix, a drain and dry fix, or is this demolish and rebuild the pool level of concern? (Hopefully that last option is in jest)


pool is in southern Florida, about 1 mile from the ocean, so we have a ~4 foot water table and sandy soil.

 

[Draddy]

Because this is TFP, what would a post be without levels…no idea if this is useful for the issue.


==========================================
------------------------------------------
Build Type: Plaster
Volume: 9800 gallons
------------------------------------------
Latest Test Result Summary:
FC: 7.5 (yesterday)
CC: 0.5 (yesterday)
pH: 7.5 (yesterday)
TA: 80 (yesterday)
CH: 325 (yesterday)
CYA: 50 (yesterday)
SALT: 3800 (yesterday)
BORATES: 15 (yesterday)
TEMPERATURE: 88° (yesterday)
CSI: -0.25 (yesterday)
==========================================

 

[mknauss]

The stains are most likely copper.
The crack -- not a big deal if just the plaster. But what caused it to crack?

 

[Draddy]

The stains are most likely copper.
The crack -- not a big deal if just the plaster. But what caused it to crack?

Thanks! Really not sure, would rusting rebar?

 

[mknauss]

You would have a large rust stain at the crack if rebar.

If the crack does not leak, grow, widen, or displace, I would not worry about it.

 

[Draddy]

You would have a large rust stain at the crack if rebar.

If the crack does not leak, grow, widen, or displace, I would not worry about it.

Good to know.
I do have two large palm trees (20 feet tall, 12 inch diameter) within 10 feet of this shallow end of the pool. Possible root damage?

 

[mknauss]

Possible root damage?

Anything is possible. But not likely. Like I said, if the crack does not change or leak, I would not worry about it. But keep an eye on it.

 

[Draddy]

Anything is possible. But not likely. Like I said, if the crack does not change or leak, I would not worry about it. But keep an eye on it.

Last question… I appreciate the help! I did find some things that look like calcium nodules….do you feel this could be related and I should begin looking for delimitation?

either way, won’t panic yet, will just keep an eye for changes.

 

[mknauss]

Could be. The crack could be from that too.

Do you know if the last replaster was a full chip out or just skim coat?

 

[Draddy]

Could be. The crack could be from that too.

Do you know if the last replaster was a full chip out or just skim coat?

I don’t know, (was done by the previous owner who was an investor shortly before putting the house up for sale…based on other repairs i know about, he was incredibly cheap, would only fix bare minimum and wouldn’t hire the best people) but I believe skim coat, and the primary reason i believe that is because the pool light is plaster in (meaning they didn’t remove ports and just plastered around them.)

though the tile does look new, not sure if that gives an indication one way or the other. The coping is original.

 

[mknauss]

Keep an eye on those areas. A full chip out and replaster is probably in your future. Might be 10 years might be next year.

 

[Draddy]

Keep an eye on those areas. A full chip out and replaster is probably in your future. Might be 10 years might be next year.

Will do, any short term bandaids? Do I need to bring my CH up? (Read somewhere that saturating the pool with calcium can slow the damage?

 

[onBalance]

The new plaster coat has delaminated and may have formed calcium nodules in those areas. Your water balanced is fine.

 

[Draddy]

The new plaster coat has delaminated and may have formed calcium nodules in those areas. Your water balanced is fine.

Did I cause this? Anything I could have done differently? Or did the last owner just hire a cheap contractor who did a poor job?

 

[zea3]

Plaster de-lamination, if I understood correctly, is a result of poor preparation, poor application and/or poor plaster quality. I doubt there was anything you could do differently.