Worrisome cracks gunite pool, shrinkage or structural?

[Pooldayeveryday]

Hi All,

We’ve just noticed a worrisome crack in the deep end corner of our gunite pool. Our pool is new, completed in the fall of 2021. The crack is thin and runs from the tile line all the way down the corner and a little onto the floor. We don’t seem to be losing water, but we are concerned because of the location of the crack. Any words of advice would be greatly appreciated!
Thanks in advance!

 

[reggiehammond]

Yikes!

 

[ajw22]

That type of crack is indicative of the deck putting pressure on the pool structure and cracking the bond beam and shell.

It does not look like you have a proper expansion joint that allows the deck structure and pool to move independently. See Expansion Joints and Coping - Further Reading

What warranty on the pool shell do you have with your builder?

Report the crack to your builder.

 

[AQUA~HOLICS]

That crack is too long to be a shrinkage crack and it appears to be in a corner that is a stress point in the shell.

 

[JamesW]

Do you have pictures of the whole pool?

It looks like a lot of banded iron stains, which usually indicates a leak.

Is the pool gunite, shotcrete or poured?

 

[Pooldayeveryday]

This crack is in the deep end corner where the deep end wall meets a corner bench. Behind this wall is the auto cover vault, so the deep end wall is extra thick to accommodate the vault . The coping on this wall does not sit directly on the bond beam, it’s on brackets so the auto cover can retract underneath it. Also, we don’t have decking surrounding the pool, we have 14” bluestone coping with grass right up to the coping, except on the shallow end, we have a patio.

We have a lifetime structural warranty.

I did report the crack to our builder, but I was hoping to get some objective opinions here.

Thanks!

 

[Pooldayeveryday]

Do you have pictures of the whole pool?

It looks like a lot of banded iron stains, which usually indicates a leak.

Is the pool gunite, shotcrete or poured?

 

[Pooldayeveryday]

View attachment 503272

It’s gunite. Those stains happened when we first filled the pool, we noticed them as soon as the water cleared after start up.

 

[JamesW]

Is the pool perfectly level everywhere?

 

[Pooldayeveryday]

View attachment 503272

The crack is in the back right corner, where the back wall meets a bench

 

[Pooldayeveryday]

Is the pool perfectly level everywhere?

I think so, but not sure. How do I tell for certain?

 

[JamesW]

Get a tape measure and measure from the bottom of the coping to the water everywhere.

Concrete can crack, so not necessarily a big deal, but you want to monitor the crack and the level to see what changes.

 

[JamesW]

Corners are natural stress points.

That’s why you never see square windows on planes or boats.

Rounded corners allow stress to flow around things smoothly.

You have a rather sharp corner, which will concentrate stress.

The concrete is probably underdesigned in strength, thickness or reinforcement.

It might also be due to some minor settlement.

 

[Pooldayeveryday]

Get a tape measure and measure from the bottom of the coping to the water everywhere.

Concrete can crack, so not necessarily a big deal, but you want to monitor the crack and the level to see what changes.

Where the crack is, there is a huge mass of gunite behind it. I don’t know if that’s good or bad. The back wall is super thick to accommodate the auto cover, the coping is 24” on that wall. And on the other wall is a bench, so also super thick mass of gunite. So it’s not like the crack is on a regular pool wall.

 

[ajw22]

Where the crack is, there is a huge mass of gunite behind it. I don’t know if that’s good or bad. The back wall is super thick to accommodate the auto cover, the coping is 24” on that wall. And on the other wall is a bench, so also super thick mass of gunite. So it’s not like the crack is on a regular pool wall.

Thickness of the concrete does not provide strength. The amount of rebar in the concrete is what strengthens it. Concrete without rebar can crack easily.

Do you have pics of the area after rebar and before gunite?

If they just put a thick wall of concrete with little rebar in it the gunite will not be structurally strong.

 

[AQUA~HOLICS]

What PSI was the Gunite?

 

[Pooldayeveryday]

Thickness of the concrete does not provide strength. The amount of rebar in the concrete is what strengthens it. Concrete without rebar can crack easily.

Do you have pics of the area after rebar and before gunite?

If they just put a thick wall of concrete with little rebar in it the gunite will not be structurally strong.

What PSI was the Gunite?

I don’t know. How would I find that out?

 

[AQUA~HOLICS]

Your builder should know and steel engineering plans should show what they required for the shoot.

 

[Pooldayeveryday]

Thickness of the concrete does not provide strength. The amount of rebar in the concrete is what strengthens it. Concrete without rebar can crack easily.

Do you have pics of the area after rebar and before gunite?

If they just put a thick wall of concrete with little rebar in it the gunite will not be structurally strong.

Thickness of the concrete does not provide strength. The amount of rebar in the concrete is what strengthens it. Concrete without rebar can crack easily.

Do you have pics of the area after rebar and before gunite?

If they just put a thick wall of concrete with little rebar in it the gunite will not be structurally strong.

 

[Pooldayeveryday]

Corners are natural stress points.

That’s why you never see square windows on planes or boats.

Rounded corners allow stress to flow around things smoothly.

You have a rather sharp corner, which will concentrate stress.

The concrete is probably underdesigned in strength, thickness or reinforcement.

It might also be due to some minor settlement.

Does it look like a serious problem to you? I’m kind of freaking out