New Pool - Cracked Grout

[jollyjeff]

We have a new fiberglass pool that was completed a few weeks ago. I noticed the grout line between the waterline tile and coping had begun to crack on one side of the pool. It has now spread over a long span and is coming out in some places. I sent pics to my pool builder.

Upon research, I've come to this conclusion:
The concrete deck is attached to the concrete coping beam by rebar. The travertine is mounted to the top of the beam by mortar. This combined structure is not connected to the fiberglass pool shell, so the expansion joint is where the grout line is between the tile and coping (since the tile is adhered to the pool wall). My PB seemed surprised by this, even though he has been in the business for quite some time. I asked him if it should have a flexible caulk like polyethylene in this joint and he said it "sounded like a good idea". He is going to try some in a small area where the grout has fallen out and see how it performs.

Has anyone else experienced anything similar to this? Just wondering if a flexible caulk will solve the issue long-term. I plan to seal the travertine and concrete after this is corrected. Pics are attached.

 

[ajw22]

You tried to do cantilevered coping but it was not installed properly.

You needed to have a decoupling joint and plastic sheet or felt paper to create a slip joint.

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.

Or you can create an expansion joint around the outside of the travertine coping and fill it with foam backing rod and Deck-O-Seal..

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

 

[jollyjeff]

Thanks. So, since the bond beam was tied to the concrete deck via rebar in our build, the diagrams you show would have them be two separate structures, correct? Our bond beam was not tied to the pool shell, but was tied to the concrete deck.

 

[ajw22]

Thanks. So, since the bond beam was tied to the concrete deck via rebar in our build, the diagrams you show would have them be two separate structures, correct?

Yes

Our bond beam was not tied to the pool shell, but was tied to the concrete deck.

So you want nothing to touch and couple between the pool shell and the bond beam, coping, or deck.