Pool under construction - should I not use flagstone on our water feature wall?

[haroldo]

We are building a SWG pool, and I have been consuming TFP's articles on pool maintenance. One of the things that caught my eye was this section from this SWG article:

"The two most common situations where damage has occurred are in indoor pools, where the FC level has been allowed to get way too high, and when you have one of the softer kinds of natural stone (sandstone, limestone, etc) above the water line, and the stone gets splashed regularly, for example in a waterfall. Even in these two situations, problems are rare."

We have this flagstone we have used on other parts of our outdoor patio, which we are planning on using on our water feature wall. I don't quite know exactly what type it is. It's some type of sandstone

Should we be concerned and use something else?

 

[mknauss]

Welcome to the forum.
I would not use any form of natural stone in or near the water such that it can get wet consistently.
Not only degradation, but calcium buildup and efflorescence is a concern.

 

[ajw22]

Welcome to TFP.

A water feature wall can get scale buildup. You want a hard tile that can be cleaned without damage.

Read Waterline Scale Removal - Further Reading

 

[haroldo]

thanks! what are some examples of materials that folks use, what exactly is a hard tile? Would travertine classify as such?

 

[mknauss]

Porcelain tile.
Travertine is soft and not a good choice.

 

[suzook]

So I guess all the pools I see with natural stone are built wrong?

 

[ajw22]

So I guess all the pools I see with natural stone are built wrong?

Depends where the natural stone is used.

You trolling or have a more specific question?

 

[haroldo]

Depends where the natural stone is used.

You trolling or have a more specific question?

We just switched the water feature wall plans from stone to tile. Thanks folks for the info.
Having said that, while I'm not sure if suzook is trolling or not, I do wonder the same. While wife and I looked through the multitude of high end pool projects and examples, a vast number of them were built with natural stone on both edge coping, decking, as well as water feature walls. These pools projects costs ranged from 200K to 500K according to different builders. So, I too wonder, are these folks simply unaware bound to find out later that this was a mistake, are builders not aware (how so?), is this not such a noticeable problem in the short term, etc? how is this such a common thing to do despite not being good for pool chemistry?

 

[mknauss]

Natural stone is very good looking when new.
Ask for pictures after 5 years. Of normal residential pools, not one that has a full time pool maintenance crew.

 

[ajw22]

a vast number of them were built with natural stone on both edge coping, decking, as well as water feature walls.

Edge coping and decking are fine. Water feature walls can be the problem area.

A water feature wall has a very different microclimate.

, are these folks simply unaware bound to find out later that this was a mistake

Yes, and then they show up here unhappy asking what they can do. Hang around here for 10+ years and you will get to meet them.

, are builders not aware (how so?),

Builders don't care.

Most builders look to give the customer what they desire. Very few will try and advise the customer differently as they have found that customer chooses a different builder who says it will not be a problem.

is this not such a noticeable problem in the short term, etc?

It takes a few seasons for problems to develop. Every pool has its own microclimate. In some pools problems may never develop. Do you feel lucky?

how is this such a common thing to do despite not being good for pool chemistry?

This has nothing to do with pool chemistry.

 

[Newdude]

These pools projects costs ranged from 200K to 500K

Perfect example. A 200k to 500k pool is likely using a higher quality bracket of materials even if the end result appears similar. Your average homeowner isn't shipping/flying in hardscaping and is using whatever is locally available on the cheap.

 

[haroldo]

Natural stone is very good looking when new.
Ask for pictures after 5 years. Of normal residential pools, not one that has a full time pool maintenance crew.

...

This has nothing to do with pool chemistry.

how so? what is the issue then? is the concern only for degradation of the stone itself and not the pool? I though the problem was with calcium hardness which the natural stone could contribute to? I'm confused now

 

[ajw22]

how so? what is the issue then? is the concern only for degradation of the stone itself and not the pool? I though the problem was with calcium hardness which the natural stone could contribute to? I'm confused now

Calcium scale forms on the stone and becomes difficult clean.

Calcium scale is caused by the water evaporating on the stone and leaving calcium residual buildup.

Pool surfaces at the waterline, spillover, and water features that have water depositing and evaporating can develop calcium scale.

Waterline Scale Removal - Further Reading

www.troublefreepool.com

 

[haroldo]

Calcium scale forms on the stone and becomes difficult clean.

Calcium scale is caused by the water evaporating on the stone and leaving calcium residual buildup.

Pool surfaces at the waterline, spillover, and water features that have water depositing and evaporating can develop calcium scale.

Waterline Scale Removal - Further Reading

www.troublefreepool.com

thanks! so I am hearing from you that the concern is with scale on the stone? a cosmetic thing mostly? That article I linked on my original post, and initial responses talking about calcium buildup and efflorescence made be think the concern was also with the pool maintenance itself. Scale build up to me sounds like a non issue in comparison. My entire house is covered in scale build up, our water is terrible , so a little stone on the pool sounds like it would be the least of our problems. Anyway, the alternative tile water feature wall design has grown on us since I started this thread yesterday, so we're going that route

 

[suzook]

We just switched the water feature wall plans from stone to tile. Thanks folks for the info.
Having said that, while I'm not sure if suzook is trolling or not, I do wonder the same. While wife and I looked through the multitude of high end pool projects and examples, a vast number of them were built with natural stone on both edge coping, decking, as well as water feature walls. These pools projects costs ranged from 200K to 500K according to different builders. So, I too wonder, are these folks simply unaware bound to find out later that this was a mistake, are builders not aware (how so?), is this not such a noticeable problem in the short term, etc? how is this such a common thing to do despite not being good for pool chemistry?

I'm not trolling. I see lots of pools with natural stone. Do they need some maintenance? Sure, but what doesn't? Especially with a pool.

 

[Newdude]

talking about calcium buildup and efflorescence made be think the concern was also with the pool maintenance itself

Let's use a 15k gallon pool as an example and it takes 14lbs of calcium chloride to raise the CH by 100 ppm. I don't care how much flakes off the stone, they are literal flakes and nothing but proverbial drops in a 15k gallon bucket.

 

[ajw22]

I'm not trolling. I see lots of pools with natural stone. Do they need some maintenance? Sure, but what doesn't? Especially with a pool.

And we are educating the OP to decide between high maintenance and lower maintenance materials.

That's what we do - education.

 

[Ahultin]

We used "flagstone" on or build and it is on the spa overflow. I think the issue is the term flagstone is used to describe a wide variety of materials. While we were shopping i asked the question of longevity straight to the quarry that our material was coming from and they stated anything that is considered a quartzite is OK for the application. We are ~3yrs in an have not had an issue.
I beleive @Dirk has some flagstone features and used some magic (read could be kinda spendy) solution that was applied and soaks into the material to increase longevity. Hopefully he can comment

 

[Dirk]

We used "flagstone" on or build and it is on the spa overflow. I think the issue is the term flagstone is used to describe a wide variety of materials. While we where shopping i asked the question of longevity straight to the quarry that our material was coming from and they stated anything that is considered a quartzite is OK for the application. We are ~3yrs in an have not had an issue.
I beleive @Dirk has some flagstone features and used some magic (read could be kinda spendy) solution that was applied and soaks into the material to increase longevity. Hopefully he can comment

As Ahultin alludes, not all flagstone is alike, and some should definitely not be used near a pool. The problem is, flagstone is basically compressed sand. If the Dude did a good job on yours some millions of years ago, you'll be OK. If not, then untreated it'll sand and flake and make a mess (on you and in the pool). And it's really hard to get him on the phone to make it right if you get a bad batch, because he's pretty old by now and he doesn't like to text.

I don't know how you go about ensuring you get "the good stuff." But if you don't, it can be treated to minimize the "deconstruction." If your builder wants to treat it, and talks about "sealer," then he probably doesn't know what he's doing. You use an expensive chemical, a consolidator, for this purpose. Sealers seal, which doesn't address the problem, but consolidators seep into the stone and "glue" the sand and layers together (I'm paraphrasing).

I didn't choose my flagstone (I bought house with pool), and while I REALLY love the look of it, I'm not sure I'd go that route if I had to do it over. I'd be tempted to use a different tried-and-true stone, or perhaps a stamped concrete. They can do amazing things with concrete, between the stamping and coloring, that rival real stone.

Keep researching and make an informed decision. You don't really get to change your mind after it's installed.

@mcleod is our stone guru, and he can check my post for accuracy. He's the guy that actually treated my flagstone.

 

[suzook]

Depends where the natural stone is used.

You trolling or have a more specific question?

No, not trolling.

And we are educating the OP to decide between high maintenance and lower maintenance materials.

That's what we do - education.

And someone mentioned completely staying away from natural stone. They made it sound like it's a big mistake. My point was natural stone is, and can be used.