Continuing Problem with cracking coping/decking

[Bill1974]

I have never used a liner drain, so I don't know much about them. But the end doesn't seem right to me and I don't see that glue on any of the pipes joints. If this is leaking water into the soil all the time, it could be the reason for the ground movement. This is right by the area of the cracking. Maybe the pipe got knocked off in the concrete pour.

 

[jcushman]

Is there a chance that water is getting past the liner drain in the deck and causing the soil under it to expand and contract? If the soil under the decking is expansive and water is getting in that could be a contributing factor. Does the cracking happen around the same time of the year? Do you have noticeably dry and wet seasons? The short wall on the pool is going to firmly hold it's place and the highest stress area is going to be where your cracking is occurring. Anther idea is that the expansion joint is not large enough to compensate, but I don't think this is the issue.

In Texas. Temperature extremes. 100+ all summer. Winter lows can be 20ish normally. Yes we have expansive soils. No idea if the drain could be leaking.
Any thoughts on the rebar issue noted above?

 

[jcushman]

I have never used a liner drain, so I don't know much about them. But the end doesn't seem right to me and I don't see that glue on any of the pipes joints. If this is leaking water into the soil all the time, it could be the reason for the ground movement. This is right by the area of the cracking. Maybe the pipe got knocked off in the concrete pour.
View attachment 424546

I suppose it could be leaking, but I don't think it was knocked off during pour, because ample amounts of water come out the drain during rain.

 

[Bill1974]

All I am aware of is that the decking should not be tied into the pool structure. The only connection there should be is the bonding wire. The one piece of rebar could be contributing to the issue. Next time work is done, severing the rebar should be done.

Have you noticed any movement in the bond beam? Looking at the picture from the deck pour, I don't see anything to create a gap between the deck slab and pool structure. That can be made by running a concrete saw down along the joint of the coping and tiles till is down to soil. Fill that gaps with a foam and flexible mastic as stated by ajw22. But I don't think the expansion of the slap and decking is that much (~.06") at max.

As I asked before does the cracking appear in a certain time of the year, when the weather changes from dry to wet, hot to cold, etc? If it gets into the 20°s I guess frost heaving might be possibility. Does the size/offset of the crack ever decrease or it only gets larger with time?

 

[jcushman]

I am fairly certain there was a foam gap. See photo in post #8. This was later removed and replaced with mastic. This has been repaired several times, so hard to tell long term if it expands or contracts seasonally or weather related. The vertical displacement you can see herehas gotten worse over the last several months. The interior of that corner is lifted above the tile while the outer corner is not lifted.



Thank you for all of your input.

 

[ajw22]

You can see the gap along the top of the tile created by the lifting.

That indicates and expansive soil problem, not just thermal expansion.

 

[jcushman]

So do you think as Bill suggested that the problem may indeed be the deck drain connection to the pvc drain pipe? Thanks for your input.

 

[ajw22]

I labeled the stones Stone1 and Stone2 so we can discuss them.

How far down does the lifting and the crack go on Stone2?

Show me pics of the length of Stone2.

 

[jcushman]

It goes about halfway the length of Stone 2.


And the one next to that - call it Stone 3 - also has some cracking


When you knock on the stones, everything from the crack in #1 to the corner, the pool side of stone 2 adjacent the crack, and some of stone 3 sound hollow and not like the rest of the coping. To the right of the cracking in #1 sounds solid.

 

[Staceyleah22]

You show all the signs of a bad expansion joint.

Hard to say where in the construction they messed up. Your builder is correct it is ground movement causing the cracks. But a functioning expansion joint should not allow movement of the deck to crack coping and tile. Good chance your bond bean will also crack.

A cracked bond beam sounds really bad. Does that lead to a leaking pool? How would they fix that?

 

[Toxophilite]

You can see the gap along the top of the tile created by the lifting.

That indicates and expansive soil problem, not just thermal expansion.

The problem with highly expansive soils, like we have much of here in Texas, is not so much the rise and fall of the total of support of a slab, but more with unequal moisture contents. A whole house rising and falling several inches from dry to wet season is normal, and unless the slab if a floating a design, post-tension, or on columns, it will eventually fail if one end stays wet and the other dries out. If the ending area at that deck beam were to experience a period of drying faster than the the supporting soil of the middle of the slab, that end would basically become free-hanging and the slab would fail there.

 

[ajw22]

What about the lift in stone2? How far back has the stone separated from the bond beam?

 

[ajw22]

The crack that runs from Stone3 to Stone2 to Stone1 is interesting. It is a continuous run through three stones and there is no deck on the side of the coping.

Usually we see cracks perpendicular to the stone, like we see on Stone1 which has two cracks.

But that long crack is through three stones and parallel with the way the stone runs.

Right now just pointing out what I observe.

 

[jcushman]

What about the lift in stone2? How far back has the stone separated from the bond beam?

The top grout line is cracked the whole length of stone 2, but the stone is only separated and raised up about halfway down. Here is about full length shot of stone 2. The far right of photo is the corner.



This is the joint between stone 2 and stone 3:


Another view:

 

[ajw22]

Show a top views of Stone2 and stone3 with whatever is to the non-pool side of it.

 

[jcushman]

As you can see, there is also cracking on the skim coat on the pool wall.

 

[Bill1974]

The cracking in the skim coat (and cracking of the coping on that section of the wall) suggests that the wall is cracked or something is going on in it. The only thing can think that would cause that is water trapped and it freezing. If that is from soil issues, it's not good (not trying to scare you), I would expect to see some evidence of a crack inside the pool too.

Does the outlet for the liner drain pool in that area or does it run off? also where does the water from what is next to the pool go?

 

[jcushman]

No evidence of crack in pool. There is one tile with a small crack (photo in post #32). Nothing pools. It all runs off. There is a natural slope away as the yard generally drops off in that direction. Here's a photo:


The plumbing line for the returns come up in that corner and split to the left for house side of pool and to the right in that wall for the far side of the pool.

 

[jcushman]

Could that be the issue?

 

[jedigrover]

In Texas. Temperature extremes. 100+ all summer. Winter lows can be 20ish normally. Yes we have expansive soils. No idea if the drain could be leaking.
Any thoughts on the rebar issue noted above?

The decking should not be tied by rebar to the pool shell. It looks like they did that all around the pool. It will be had to predict where cracks will occur, but concrete does expand and contract with temp changes; and as you noted, we have expansive soils. Whatever is weakest will fail first & the failure may prevent or delay other cracks. But this needs to be remedied before you get bond-beam issues. Based on the cracked tile, you already may have some cracks forming there.