Cracks in original coping - Why?

Bam Bam

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Sep 14, 2019
137
Columbia, SC
I just finished a major pool patio renovation by adding bluestone all around the pool. The mason laid the bluestone on top of the existing concrete coping then built up the weed and critter habitat to the height of the coping which was about 3”. I have just started noticing vertical cracks in the coping that appear to be at original segments, horizontal cracks in the tile and another horizontal crack on the coping. In addition to the tons of rock added to the area we have had over 20 shallow minor earthquakes (all in the 2s) within 10 miles of my house. I’ve only felt two of them though!

The crappy caulking job is another problem but that predated this issue so I’ve adjusted.

Anyone have any ideas what’s going on? Should I get a structural engineer consult? I wanted to enjoy this pool season and many more but if it turns out to be a costly repair I’m taking the money and running, ie, selling the house in a NY minute!



Thanks.
 

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Toxophilite

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From the previous coping pics, it looks like your original coping was wide and also part deck, which is its own issue. You now have the weight of decking on top of those slabs, so they probably are giving to the load in the form of cracks. Shame, because that's some beautiful stone. We wanted bluestone originally, but getting it here is very costly.
 

Orion7319

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The tile mason should have known better. Contractors in Columbia seem to do weird stuff. I know a guy who used to live in Columbia. Brand new house, was hot all the time though. He finally went into his attic one day and no insulation to be found anywhere.

EDIT: If you want to move to York, my sister in law has her house listed and she just put in a new fiberglass pool…
 

Bam Bam

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Sep 14, 2019
137
Columbia, SC
You said it - them and doctors! Yes toxophilite, coping and deck were one and the same.

Thoughts as to whether these are just growing pain “aesthetic” cracks or should I be concerned about structural concerns? I’m sure if I asked the mason I’ll get “I never saw that before”. too bad because he ranked as one of my best contractors. I’m also dealing with a problem with a sealant he applied but that’s not as concerning as the cracks.
 

Orion7319

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Jul 1, 2020
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You said it - them and doctors! Yes toxophilite, coping and deck were one and the same.

Thoughts as to whether these are just growing pain “aesthetic” cracks or should I be concerned about structural concerns? I’m sure if I asked the mason I’ll get “I never saw that before”. too bad because he ranked as one of my best contractors. I’m also dealing with a problem with a sealant he applied but that’s not as concerning as the cracks.
I’m not sure, I don’t know much about concrete.. There are folks on here though that install pools and hopefully they will chime in. It does make sense to me that if the concrete underneath is cracking it would start doing it at the expansion joints.
 
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Bam Bam

Gold Supporter
Sep 14, 2019
137
Columbia, SC
The tile mason should have known better. Contractors in Columbia seem to do weird stuff. I know a guy who used to live in Columbia. Brand new house, was hot all the time though. He finally went into his attic one day and no insulation to be found anywhere.

EDIT: If you want to move to York, my sister in law has her house listed and she just put in a new fiberglass pool…
No more houses for me! But I’m sure hers must have sold by now...Thanks! Does SIL want to move to Columbia?
 
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Toxophilite

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You said it - them and doctors! Yes toxophilite, coping and deck were one and the same.

Thoughts as to whether these are just growing pain “aesthetic” cracks or should I be concerned about structural concerns? I’m sure if I asked the mason I’ll get “I never saw that before”. too bad because he ranked as one of my best contractors. I’m also dealing with a problem with a sealant he applied but that’s not as concerning as the cracks.
It's kind of a compound problem. The bond beam of the pool was never independent of a deck, and the deck and pool were not allowed to move independently. Apparently, that never issued for you. Now, in some fashion, there's another deck on top of the original coping/deck. Could be old coping cracking is all that happens, or, could eventually crack your pool as well. No one can predict that.
 

ajw22

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It looks like you lack a proper pool expansion joint.

The pool and the deck should be able to move independently. They should not be touching. Movement of the deck will put pressure on the pool bond beam and coping and cause the type of cracks you see.

To keep it from happening a pool expansion joint needs to be cut between the coping and deck.


Pre-Cast_Coping.png
 
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Bam Bam

Gold Supporter
Sep 14, 2019
137
Columbia, SC
It's kind of a compound problem. The bond beam of the pool was never independent of a deck, and the deck and pool were not allowed to move independently. Apparently, that never issued for you. Now, in some fashion, there's another deck on top of the original coping/deck. Could be old coping cracking is all that happens, or, could eventually crack your pool as well. No one can predict that.
There were seams In the original cope/deck combo. Perhaps they were deliberate expansion joints or just the shape of the forms used to pour the concrete. Now those are covered with the bluestone. Did those have any purpose with respect to pool structure? If so, I could have mason cut through the stone above those channels. It would of course be a mess to look at it. I’d rather that than a cracked pool!
 

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Bam Bam

Gold Supporter
Sep 14, 2019
137
Columbia, SC
It looks like you lack a proper pool expansion joint.

The pool and the deck should be able to move independently. They should not be touching. Movement of the deck will put pressure on the pool bond beam and coping and cause the type of cracks you see.

To keep it from happening a pool expansion joint needs to be cut between the coping and deck.


Pre-Cast_Coping.png
There never was a separate coping. Just that concrete surround which I suppose is a coping/deck combo. The pool was built in the late ‘80s.
 

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ajw22

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There never was a separate coping. Just that concrete surround which I suppose is a coping/deck combo. The pool was built in the late ‘80s.
There is always an expansion joint. Someone needs to understand how your pool was designed.

Either that is poured in place coping and it is part of your pool structure or you have cantilevered coping. I think it is poured in place coping and your added bluestone coupled the coping to the ground.

Did you read the wiki and look at the different structures discussed?
 

Brian Malone

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Apr 16, 2013
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I just finished a major pool patio renovation by adding bluestone all around the pool. The mason laid the bluestone on top of the existing concrete coping then built up the weed and critter habitat to the height of the coping which was about 3”. I have just started noticing vertical cracks in the coping that appear to be at original segments, horizontal cracks in the tile and another horizontal crack on the coping. In addition to the tons of rock added to the area we have had over 20 shallow minor earthquakes (all in the 2s) within 10 miles of my house. I’ve only felt two of them though!

The crappy caulking job is another problem but that predated this issue so I’ve adjusted.

Anyone have any ideas what’s going on? Should I get a structural engineer consult? I wanted to enjoy this pool season and many more but if it turns out to be a costly repair I’m taking the money and running, ie, selling the house in a NY minute!



Thanks.
I can't give any advice on the crack issues but I can say your bluestone looks beautiful. I hope those in the know on the TFP forum can help you.
 
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Bperry

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Looks like original decking is cantilever. If it was cracked or moving, then anything installed on top of it will move (and crack) as well.
 

ajw22

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I’m curious how an expansion joint works on cantilever? Is it just a movable joint between the bond beam and the deck?
Movable joint? The joint does not move.

The cantilever forms a gap between the coping/deck and the bond beam. That is why it is called cantilevered as it overhangs the bond beam without touching it.

A “decoupling” expansion joint should extend across the entire width of the top of the bond beam to allow the deck to move independent of the pool shell. This joint can be created with a 4mm plastic sheet or 2 layers of roofing felt underlayment.

Cantilevered_Coping.png
 

Toxophilite

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I think in this scenario, the "slip" for lateral movement if cantilevered would not have mattered. I would bet the crack came about due to the vertical expansion, or in this case the compression of added slab/tile, which would far exceed any amount that expansion joint was intended to control on the vertical.
 

Bam Bam

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Sep 14, 2019
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Columbia, SC
The wiki reminded me that I concluded it was cantilevered too when I researched another problem a few years ago. I’m going to call a structural engineering firm Monday. I think this is too complicated and becoming emotional for me to figure out and direct someone to remediate. Thoughts?
 

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