Concrete Cantilevered Coping - Does Coping Need to be Separated from Decking?

[Harbinger of Fun]

I am having my old aluminum bullnose coping and concrete decking repaired/replaced with cantilevered concrete coping. It's a vinyl-lined pool with wooden walls. The decking and coping is being poured continuously as one pour and will extend over the top of the now flat liner track. Previously, the decking was poured continuously on top of the pool wall and aluminum bullnose coping and never caused an issue. I ended up having a question of how the expansion and contraction of the deck wasn't putting stress on the pool walls since the deck was sitting on the pools walls. The company I've hired does a lot of vinyl pools with this style of cantilevered coping, without an expansion joint between the coping and the rest of the decking, and they assure me that this is not an issue. Instead they are placing control joints perpendicular to the pool edge roughly every 4-6 feet.

In the diagram below, it's implied that the coping "expansion joint" in this context can just be the concrete not connected to the pool wall. However, the liner track has ridges about a half inch high which I think will not permit the decking to slide over the top of it.

Any experienced people out there that can confirm or deny that this is an issue I should be worried about? They have yet to pour the decking. If this may be a problem, what is the "solution?"

 

[ajw22]

This diagram is for a gunite pool with cantilevered coping and does not apply to your situation. With a gunite pool you have two separate solid concrete structures between the pool and the deck that need to be separated and move independently.

Your pool walls are steel and relatively flexible compared to a gunite structure. The cantilevered deck tied to the steel walls will move the pool structure in the hole in the ground as it moves. If you have major deck movement and concrete cracking it can damage the pool wall. That is a risk you take in creating one monolithic structure.

Concrete control joints are for a completely different problem of trying to focus the inevitable cracks in the concrete deck at those control joints. It has nothing to do with expansion joints.

 

[Harbinger of Fun]

This diagram is for a gunite pool with cantilevered coping and does not apply to your situation. With a gunite pool you have two separate solid concrete structures between the pool and the deck that need to be separated and move independently.

Your pool walls are steel and relatively flexible compared to a gunite structure. The cantilevered deck tied to the steel walls will move the pool structure in the hole in the ground as it moves. If you have major deck movement and concrete cracking it can damage the pool wall. That is a risk you take in creating one monolithic structure.

Concrete control joints are for a completely different problem of trying to focus the inevitable cracks in the concrete deck at those control joints. It has nothing to do with expansion joints.

Makes sense, I appreciate the explanation.