problem with blotchy pebble surface

[DanManSanDiego]

Greetings all. Built the pool of our dreams last year--finished just about late July 2021 and overall very happy with features and functionality. However, very unhappy with the pool mini pebble surface. We went with a light color--I believe NPT Aqua Cool Mini. Unfortunately, the surface is mottled and blotchy with uneven coloring everywhere and major dark blotches in deep end (7.5 feet). Our pool is fairlly large--about 32,000 gallons and 60 x 15ish. The pebble subcontractor did the entire job in one day, including the acid wash in the afternoon (Pool builder subcontracts shotcrete and plaster/pebble finishing). We did not question their process since this is our first (and last) pool and we assumed their expertise. However, the result looks bad, especially on cloudy days, evenings and under light. We have complained to pool builder who has sent the subcontractor back a couple times to address issue. Once, they poured some acid by tube directly to the large splotchy deep end discoloration and said it would lighten up soon. However, it's been a year and it's no better. We have paid in full, but our pool builder recognizes that this is unacceptable and they are holding the subcontractor responsible since the warranty comes through them. They no longer use this subcontractor due to similar issues--but that's certainly no comfort for us. At this point, the builder is recognizing their responsibility to make this right--but the first step is for the (incompetent in my view) subcontractor to return and attempt to fix.

For you experts out there with more experience than me--are we right in rejecting this result? I accept that workmanship will vary and this is more of an art than an exact science. I'm OK with some variations, but this seems really unacceptable. Plus, we paid an extra $9600 or something like that to go with the specialty finish. Is there anything that can correct this short of draining the pool and resurfacing? Did our selection of light color contribute to this problem? I believe the subcontractor rushed the job and did the acid wash before the surface was evenly dry, resulting in the overall blotchiness and the extreme discoloration at the deep end. I welcome any thoughts and recommendations. I've attached photos of our pool and the shots of the overall blotchiness and the extreme dark blotch at deep end.

 

[Dirk]

Personally, I would find that unacceptable, too, though it's hard to tell for sure from images. But since you've got the builder agreeing with that conclusion, that seems to be a fair assessment.

It's usually dark colors that mottle more than light ones, and mottling is somewhat inevitable. But my understanding of mottling is that it occurs over time, and over the entire finish, not in big clumps like that.

The acid washing of a new pebble finish generally occurs the next day. But I don't know what symptoms might occur if it's done sooner.

But what I do know, is that the additional application(s) of acid (1) always seems to be the go-to move for any sort of finish issue, and (2) it rarely solves any finish issue beyond perhaps a temporary disguising of the underlying problem. In all cases, acid washing doesn't magically remove the problem blemish or discoloration, and leave your original finish intact. What it does is remove a layer of your finish, and sometimes takes some stains and discolorations with it (but rarely all the stains, and rarely leaves a perfect looking result). An acid wash will leave you with a rougher/etched, weakened finish with likely a shorter lifespan. In the case of plaster, it won't feel as nice. In the case of a pebble finish, you run the risk of the pebbles falling out of the plaster substrate. Neither finish will likely last as long as it would have without the acid wash. And in many cases, the original blemish issues come back anyway. In short, don't let anyone talk you into an acid wash as a fix.

If this was a name brand finish, like PebbleTec, it is PebbleTec that honors the warranty, though usually through the original installer, who is supposed to be certified by PebbleTec. Other manufacturers might have similar arrangements and warranties. You should have been given paperwork that specifies the warranty and the manufacturer. So if the sub won't deal with this properly, then your recourse would be to go directly to the finish manufacturer. That is not a guarantee that they'll pay to fix it, but it would be the next step.

Now if this was a sub that "mixes up their own finish," without the backing of a big manufacturer, then you are completely at his mercy, obviously.

Let's see if @JoyfulNoise or @onBalance can give you some insight into the cause of the issue, and if so maybe you can use that as ammo.

 

[Dirk]

Oh, to answer your question, the fix is replacement, so yes, draining the pool, chipping it out, and applying a new finish. Or a significant discount and you live with it. Though if it is a symptom of incorrect installation, the full ramifications of that may surface in the future with some other problem.

If it comes to replacement, some will just scratch the surface and apply a new coat (simplified description). Others will do what's called a full chip out, removing the finish down to the gunite, and then applying a new finish. The full chip out is the better fix, because it ensures better adhesion. The cheaper method might be OK under certain circumstances, but I don't know what they are. Perhaps our experts can better explain that. But I wanted to make sure you were aware of those possibilities.

 

[JoyfulNoise]

Not much more can be said. I think @Dirk hit all the high notes.

On a philosophical level, at least the pool is still swimmable and this is mostly a cosmetic issue. It looks like you spent a lot of money on your dream pool so I’m sorry it’s come down to this. Cosmetic problems don’t necessarily imply structural problems but the more that the surface is “fiddled around with” the more likely it is going to be damaged.

 

[DanManSanDiego]

Not much more can be said. I think @Dirk hit all the high notes.

On a philosophical level, at least the pool is still swimmable and this is mostly a cosmetic issue. It looks like you spent a lot of money on your dream pool so I’m sorry it’s come down to this. Cosmetic problems don’t necessarily imply structural problems but the more that the surface is “fiddled around with” the more likely it is going to be damaged.

So we're in the process of having the pebble subcontractor do some serious underwater buffing. It may be a bit better but still very noticable blotches. Will update when we have a result and conclusion. Thanks for the helpful information. Seems to be a bit of cost/benefit analysis involved in all these types of decisions.

 

[Dirk]

Seems to be a bit of cost/benefit analysis involved in all these types of decisions.

Definitely. Fingers crossed that it's not just your cost and the sub's benefit!!

 

[DanManSanDiego]

LOL! at least it helps to laugh...Just realized a possibly bigger issue with some possible pool settling. A little research shows me I'm not alone with that either. Got a call in to pool builder to find out how big an issue--maybe water leak?

 

[Dirk]

Yikes. Well, hopefully he'll honor his warranty. My deck is sinking, but it's taken about 10 years or so. Shouldn't be happening like that, and there should be no settling anyway. That's what compacting is for, which I've been told is what was missing from my deck's installation. It's an all-too-common shortcut, because it saves time and money and usually doesn't rear it's ugly head until the contractor is long gone. I have no recourse. So in a way, it's better that this has happened to you now. I know that's like telling someone that barely survived a horrible accident that they were lucky! But that's all I got for ya...

 

[DanManSanDiego]

Yea, I'd be happier if it were the deck sinking rather than the pool as it appears to be. PB is going to inspect in person and we'll see what they say.

 

[Dirk]

Oh, it's your pool sinking? Wow. There has to be an expansion joint, to separate pool shell from deck. I get that. But I wish there was a better way to keep the two aligned, so this issue can't happen, regardless of which part is moving. Probably not possible. Keep us posted.

 

[JoyfulNoise]

Soil analysis is a critical part of any pool design. The PE that signs off on the design usually needs to know that detail so that the shell can be properly designed to distribute the load evenly. In some cases, piers and footers need to be added to a pool shell design to stabilize it or if native soils are considered too expansive then chemical remediations may be called for to reduce soil expansion and movement.

Too late now, but hopefully the PB did his homework in that regard.

 

[DanManSanDiego]

Still waiting to have PB come inspect. However, I don't think it can be a minor thing. City inspection didn't require a soils report to my knowledge--and PB said if we kept depth under 7.5 feet no special engineering was needed. Pool inspector praised the work and said it was first rate. However, that remains to be seen in the big picture. Will update and maybe start a new thread when I know more.

 

[Toxophilite]

Yea, I'd be happier if it were the deck sinking rather than the pool as it appears to be. PB is going to inspect in person and we'll see what they say.

If it was located here, it would be just as likely, to a tad bit more likely, that the deck experienced a rise. I wish you good luck with this issue!

 

[DanManSanDiego]

We'll see what the verdict is after laser level measurements and the like. Could be trouble in paradise!

 

[Toxophilite]

We'll see what the verdict is after laser level measurements and the like. Could be trouble in paradise!

If you find a piece of clear hose at the hardware store and don't mind taking a swim, you can get just as good an answer yourself: How to Use a Water Level: 13 Steps (with Pictures) - wikiHow

 

[DanManSanDiego]

If it was located here, it would be just as likely, to a tad bit more likely, that the deck experienced a rise. I wish you good luck with this issue!

I apologize for delays in reporting here. Just settling down after a cruise to celebrate our 50th and then a bout of covid to celebrate our cruise. Regarding the pool, it's rock solid and level. It's the deck that's risen up on the shallow end by about an inch. Expansive soil is the culprit, and the hardscape contractor (not the pool builder) is discussing repair options with me. Glad it's not pool, but unsure what fix is for flagstone deck other than removing the raised portion and redoing--after treating the expansive clay soil as should have been done originally. Oh, and the blotchy pebble surface--it's still there, but more muted after directed buffing. I expect we'll have to live with that as I really don't see us taking legal steps to force a compete refinishing--which I think it would take to correct. So, does anyone have any good suggestions for our raised flagstone deck issue? thanks in advance

 

[JoyfulNoise]

The key to expansive clay soils is to maintain a constant water content as much as possible. If the clay dries out and rehydrates, the swelling and contracting is going to move anything you put on it. Perhaps consider a hardscape option that allows for water penetration or is a bit forgiving if the soil the needs to move. A former TFPer in Texas installed a drip system to keep the ground around his pool at a more consistent moisture level.

 

[Toxophilite]

There's really no "treatment" for the clay soil. Next best is to take out several feet and replace with select fill, but even that will not cut all movement out of the equation. A foundation engineer once advised me to expect about 1/2 the movement with soil replacement. The soil foundation will always be clay that pushes up against anything you put. @JoyfulNoise is correct. If you want consistency and least movement, you control for the moisture content between wet and dry seasonal cycles. In this part of country, we use foundational drips and heavy mulching. Or, when stays too wet, french drains.