Need urgent help with cracking/leaking pool on a hillside in Austin, TX!

atxneedshelp

Member
Nov 3, 2018
12
Austin, TX
Hello!
I have a pool that is a little over 2 years old. It is on a hillside in Austin, TX so the back wall of the pool is about 13' tall. The front side meets up with our back patio and no wall was built on that side. The pool builder originally sprayed gunite on 3 walls with rebar (not the front side against the house foundation). Then they added dirt fill into the structure. Then they built the top layer (which has the pool shell) with just a single mat rebar on the pool bottom (instead of double mat or using piers). We are experiencing cracks along the back and side edges of the pool. There are definitely structural issues due to faulty construction (not built to an engineer's standard). We have consulted with three structural engineers and they all have different opinions. One says to tear it down and start over, one says to get geotechnical engineering opinion, and one says to build piers under it now to fix any structural issues (then we wouldn't have to rely on the fill below and a single layer of rebar to hold the pool up). Our builder is willing to add in 8 piers under the pool to provide the necessary support but we are not 100% positive that is a permanent fix and we are not sure if we will need to get into a lawsuit if we need to tear down our pool and rebuild. The piers would be tied into the existing rebar and the pool would be re-plasters (Pebblesheen) afterwards.

Has anyone else dealt with this? Will piers stabilize the pool structurally and prevent future cracking and leaks?

Thank you for any help and ideas!

2018-06-01 10.32.23.jpg 2018-10-30 15.48.50.jpg
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to TFP! :wave: Sorry it's under such circumstances. It might be tough to get an accurate answer from TFP by just reviewing your situation from our computer screens. We do have tons of various members who work in occupations that may see your post and have some good expert advice. The external dripping markings would seem to be signs of efflorescence and also noted on this thread: efflorescence?. As you can tell from the discussion, some seepage is considered normal, but in some cases a sign of something worse. In your case, if you are obviously noticing movement in the structure, I suspect those water mineral marks are a byproduct from that movement. Here's a question …. Are you losing water inside the pool?

Our soil just south of you stinks. Unless you are just west/east of San Antonio where the bedrock seems to be more at the surface, it's that ridiculous black "gumbo" clay. I had to have some steel piers placed under my garage last year. The results were immediate as the piers lifted the floor of the garage to where the sheetrock cracks disappeared.

Of course a pool, especially one your size and location, may not be as straight-forward. But before assuming the worse and thinking of a legal battle, I would give the builder the opportunity to try and make things right. If they think they can dig down & under the shell and wall foundation to punch piers down to bedrock, let them try I suppose. The worse that can happen is it doesn't work and you try arbitration. I sure hope it doesn't come to that. You have a lovely pool with a gorgeous view. I hope you get more advice and some positive results soon.
 

JamesW

TFP Expert
Mar 2, 2011
16,589
Have you had the pool surveyed to see if it's sinking?

What was applied to the gunite on the back wall to cover the gunite?

Can that coating be removed easily to get a better look at the gunite?

What were the original engineer's specifications that were not followed?

What does the original engineer say?

The efflorescence indicates that you're getting a lot of water buildup behind the wall that's leaking through the cracks.

Do you have construction pictures?
 

atxneedshelp

Member
Nov 3, 2018
12
Austin, TX
Thanks Texas Splash! I will check out the other post you linked (I am obviously new here!). Our grass below the pool has been "swampy" ever since they filled the pool with water so I imagine it is losing water. It seems to magically rain every time I turn off the autofill to attempt to see how much water it loses. And no matter what I see it losing, the pool guy would say that is normal (but I know it isn't). They did do a leak check though and it was definitely leaking where the long crack at the bottom of the pool is. They did fill that one in with epoxy but the pool seemed to still be leaking from elsewhere since my grass never dried up over the summer. The soil here (west Austin) is pretty shallow and sits on limestone so typically there aren't a ton of foundation issues. My home builder is definitely willing to fix it which is awesome! That makes me worry that they know about the other options...
 

atxneedshelp

Member
Nov 3, 2018
12
Austin, TX
Thanks so much for replying JamesW! The pool decking that butts up next to my back patio has dropped down maybe just 1/8" or so (I haven't measured exactly) which has caused the caulk at that interface to crack. But that was poured separate from the pool (but lines up with the coping).
I can't remember what they call it (the word has escaped my mind) but it is almost just like paint on that back wall. It isn't like a full stucco treatment (no mesh) but I forget what it is called.
That coating on the back wall has chipped at the bottom so it is probably easy to get a look at the gunite.
It is not clear to me if there even was an engineering plan when it was built (my home builder does not seem to have it from the pool builder and it sounds like any engineer would have drawn plans with double mat rebar or piers). I requested the original plan but my builder did not give it to me (because I don't think the pool builder gave it to them). They were the ones who hired this pool builder and were supervising him. I wish I was allowed to pick my own pool builder! They no longer use this pool builder (not surprising).
Yes! I have a whole bunch of construction pictures that I took (thank goodness) so I have shared them with a few structural engineers but they all have different opinions so I am a bit stumped. I am not sure how to share the construction pictures on here though due to the size limitation.
I guess basically I need to understand if we add 8 piers under the existing structure, if that really could stabilize it. I worry the bottom might be stabilized but that the weight of the water on the exterior walls could push them out and create cracks again at the base of where the floor and wall meet up. I know after they applied the gunite to the pool that they did go back and add "staples" to better connect the floor and that outer wall. So maybe the piers will be the ultimate fix? They do keep saying that all pools leak (really?) so we might create a weep hole in the floor at the center base of the pool and put in something like a french drain to drain any leakage off my lawn into the green belt so that my lawn is finally not swampy at the base of the pool.
Thanks!
 

JamesW

TFP Expert
Mar 2, 2011
16,589
It's hard to say what the piers might do. There are many different factors that determine the stability of the final product.

Concrete thicknesses and strength. Rebar sizing and spacing. Pier design and integration etc.

It seems that even the engineers are not sure what the outcome will be.

I suspect that you would need a geotechnical engineer to do an in-depth analysis of the existing structure and design a plan to reinforce the structure.

Trying to retrofit the reinforcements after the fact is always going to be more difficult and expensive than doing it right the first time.
 

Arizonarob

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Mar 25, 2018
2,867
Chandler Arizona
You can upload your photos of the build to a hosting site (photobucket, google, etc) then post a link here. It will help the pros greatly to see how your pool was built.
I wish you luck on that repair/redo. :cheers:
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,746
Northern NJ
Hello!
We have consulted with three structural engineers and they all have different opinions. One says to tear it down and start over, one says to get geotechnical engineering opinion, and one says to build piers under it now to fix any structural issues (then we wouldn't have to rely on the fill below and a single layer of rebar to hold the pool up). Our builder is willing to add in 8 piers under the pool to provide the necessary support but we are not 100% positive that is a permanent fix and we are not sure if we will need to get into a lawsuit if we need to tear down our pool and rebuild.
I evaluate your options in terms of likelihood of success:

- Tear down and start over with the proper engineering, design, and construction should give you a lasting pool, Probably the toughest in terms of disruption and conflict with the PB.

- I do think you need to get a geotechnical engineering opinion. Has anyone done any test holes in your grass area to determine how deep the bedrock is and the soil composition you have? I don't know how you can evaluate the builders plan and probability of success without an engineering analysis supporting it.

- Is there an independent engineering plan supporting what the builder wants to do? His engineering for the original pool was flawed. What time frame will the builder guarantee the fixed pool from shifting or cracking? If pool on piers have problems will the builder agree to tear it out and rebuild it then? The piers are a gamble without independent engineering validating the plan. Do you feel lucky today?

That vertical back wall, without ground behind it to support it, may need to have some supports running from it to the grass area to prevent it from shifting out. Or a layered retaining wall going up maybe halfway. Especially if the shell has insufficient rebar and gunite to give it the strength it needs to be solid independently. I had some experience with L shaped concrete storm drains that cracked.

We recently had another member in Texas post about a similar pool problem. His pool was on a slope and it looks like water eroded the soil under it and one side of the pool has sunk and has about a dozen cracks. This thread -- 17 cracks!!!

Pool Engineering, Inc., Structural Design of Swimming Pools and Residential Improvement Structures is mentioned in that thread.
 

Arizonarob

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Mar 25, 2018
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Chandler Arizona
I am by no means an expert, but looking at the rebar on the exterior wall, looks weak at best. But good job on the pics, and let’s wait for the experts to have a look.
 

JamesW

TFP Expert
Mar 2, 2011
16,589
Looks like some serious structural cracks.

Realistically, a qualified engineer is going to be needed to evaluate the existing structure and determine if reinforcements will be a viable solution or not.

They might need to do core samples of the concrete and/or the ground to determine what the conditions are.

I don't think that piers will make any difference to the way that the cracks are developing. They might help some under the wall to support the wall but getting them under the wall would be difficult at best.

Piers will mainly prevent sinking, which I don't think is the issue.

Looking more closely at the construction pictures, it seems that there is something odd about the gunite where the cracks are.

The color seems different.

The wall is so tall that it's going to put greater than normal stress on the transition from wall to floor.

In my opinion, there should be extra support going into the ground straight down from the wall to support the wall so that the force is not transferred to the floor.

The transition should be extra thick with larger rebar to take the necessary stress.

The transition also requires extra care as to the application of the gunite/shotcrete to avoid weakness. Rebound, or cold joints need to be avoided and the mix needs to be just right.

If the concrete was too hot or too cold or too wet or too dry, that can affect the strength. You would also want a stronger than usual concrete mix for this job. A standard mix is not adequate.

Many pools can be done without a detailed engineering plan because they are simple.

This pool is not a regular simple pool and absolutely requires a detailed engineering plan. Regular construction procedures and materials are not adequate.
 

riley00dog

Gold Supporter
Nov 14, 2017
2,213
Brisbane, Qld, Australia
Oh gee. I don’t have any expert advise for you, but just wanted to say good job on documenting the build so well. If that were my pool I would be pushing for a full redo, as heartbreaking as that would be. It’s good that the home builder is wanting it fixed. I hope the Pb isn’t difficult to deal with. Hopefully that will be the hb job not yours. I’m honestly a bit shocked to see that they have tried to fix some of those cracks. All the best finding a solution.
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,057
San Clemente, CA
The back wall was grossly underbuilt and their method of constructing it didn't help.

Were any Soil tests done? Were compaction tests done on the backfill? Was this permitted/inspected?

Was the pool shell was actually engineered? One of your previous posts seemed to mention is wasn't.

This really is a shame because that's a beautiful pool in an amazing setting...
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,057
San Clemente, CA
The cracks that run parallel to the back wall at the cove transition are a dead giveaway of the lack of reinforcement for that freestanding wall. That section of the pool receives the highest amount of stress since the force on that location increases exponentially relative to the height of the wall - basically a giant lever against the floor.

The freestanding pool walls that I have seen have so much rebar in them that you almost can't see through them. On two occasions a custom shotcrete mix had to be used that had plasticizers in the mix to make the shotcrete able to make it through the rebar cage. Two deputy inspectors had to be there to oversee the entire operation and verify that no voids, rebound or cold joints we created in specific areas.

Both of these walls had massive keyways. They were 1/2 the width and depth of height of the wall.
 

JamesW

TFP Expert
Mar 2, 2011
16,589
After reviewing all of the pictures, the cracks make more sense. I suspect that the bottom is basically falling out because it’s not being supported at all because it was built on 8 feet of uncompacted backfill.

Pictures 52 through 62 show that the pool is sitting on about 8 feet of uncompacted garbage backfill? Is that correct?

It looks like they flashed up some gunite to make some cheap 8 foot walls and then backfilled with garbage backfill and then built the pool on top of that?

In my opinion, if you show an engineer the construction pictures, they will tell you that it won’t last.

In my opinion, the pool is sitting on top of a structure that's not even remotely strong enough to support it.

In my opinion, trying to successfully reinforce this would be extremely difficult.

In my opinion, you should consult an engineer that designs pools and have them review the current work.

Pool Engineering, Inc., Structural Design of Swimming Pools and Residential Improvement Structures

ENGINEERING 303: Pier

Swimming pool construction in Austin TX | Master Pools of Austin
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,490
Tallahassee, FL
Were there any inspections done on this pool during the build?

Listen to JamesW and Bdavis466. They are our go to guys for good builds.

What a shame this was not done right to start with. That is such a pretty setting and view!

Are you in the house yet?
 

atxneedshelp

Member
Nov 3, 2018
12
Austin, TX
Thanks so much everyone for your input! The history of this is our homebuilder would only let us use their poolbuilder to build our pool (so we couldn't choose). The pool contract though was with our home builder. Towards the end of the construction of our pool, they basically "fired" the pool builder and brought in some other people to fix some issues in plumbing and other things. We have been suspecting a leak from fairly early on since our grass below was wet but the builder was wondering if it was a spring or sprinkler leak. Then we started seeing the cracks so they drained the pool and cut them out a bit and filled in with epoxy as a temporary fix over the summer and to see if more cracks arose. This allowed us to use our pool over the summer and now they want to offer the 8 pier options to basically support the entire structure so that the poor fill/debris that is under the pool doesn't have any play in supporting the pool. Even if the pool is supported on piers that are down into the rock bed, I have been suspecting that the back wall is still not sufficient enough to hold the weight of the water. They have a licensed structural engineer though that is coming up with the pier plan so he seems to think it will work. But the first structural engineer we hired said it won't work and the second one said we need a geotechnical engineer to determine more.

I believe the pool builder likely didn't use engineering when they built our pool but I don't know for sure. Our home builder hasn't shown us any engineering plans and kind of shrugs their shoulders when I ask about them. I am also unsure about the insurance he had and it sounds like faulty construction is not covered by his insurance (if he had it). So then it would go on the home builder's insurance but it might not cover it either? Our home builder is well-respected and have been fixing other issues during our 2 year home warranty period. They are very willing to do this pier fix but are obviously not willing to tear it down and start over. Does anyone know if the pool builder or home builder's insurance policies would pay out a cash settlement for the demolition and re-build of a pool if it is due to faulty workmanship?

We have been in the house for almost 2.5 years. I don't know about soil/compaction tests (our home builder was supposed to be supervising this pool build). I do know it is difficult to dig a hole here though since you run straight into limestone so I wouldn't think the soil should be such a big issue since they didn't have to dig down far to hit rock. Now the soil they added into the base of the foundation is another thing. And you can see all the debris that they left in there which likely decomposed. The one structural engineer assumes the fill has settled a couple inches down so the pool floor is likely no longer sitting on the fill.

As far as inspections, I am not sure what all they had to get since we are not in the city of Austin (ETJ which is not as stringent).

(And thank goodness I took a lot of photos during the building process!!!)
 

PoolGate

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Jun 7, 2017
3,814
Damascus, MD
Wow. I feel very bad for you. I suspect if a county inspector came-out he would condemn the pool and order it emptied and not used until remediated. Your pool has 5 o'clock news written all over it. Good luck and get a good lawyer I suspect to get this corrected is a complete rip-out and do-over.
 

JamesW

TFP Expert
Mar 2, 2011
16,589
In my opinion, there is no way that an engineer had anything to do with the design of the pool.

If you're asking directly if an engineer designed the pool and they're not saying that it was designed by an engineer, it probably wasn't.

I think that the pool is probably being supported only by the walls and not the fill.

If anything, the fill is now pressing outward on the walls creating more issues.

The walls are beginning to crack. So, that's a bad sign.

If the back wall goes, the whole thing is coming down.

Piers and beams might provide proper support, but how will it be done?

Maybe if they go under the pool and remove the fill then install a complete pier and beam structure that will support the entire pool, it might work.

I would want the beams to go the entire length and width of the pool including under the pool walls.

Do you know the proposed design of the piers and how they will be installed?

In any case, you need a qualified engineer who specializes in pools to determine what the best course of action is.