Leaking 50 year old mosaic tile indoor pool - considering the options

[oh_me_oh_my]

Hey all,

It's looking like finally time to address the water loss in our beautiful 20,000 gallon mosaic tile lined indoor pool. What used to be a small water loss has started to approach a few inches a day (clearly too much).

This leads us to the following options:

Option 1 - Try and identify where the leak is (leaks are) and have the tile removed, crack fixed, and new tile patched in. Pros: likely the least expensive. Cons: may not fully solve the problem if there are multiple leaks, problem may also come back.
Option 2 - Install a commercial (thick, multi-layer) liner. Pros: definitely will provide a long term waterproof membrane. Cons: definitely not inexpensive, no more beautiful tile.
Option 3 - Complete renovation of the pool - strip all the tiles, fix cracks, waterproof the shell, install new tile and grout. Pros: beautiful tile pool. Cons: very expensive, and concern the shell cracks may come back?

Any thoughts on our options? We have been in this house eight years now, the pool is 50 years old. This is indeed our forever home, but the cost of Option 3, and the concern that the problem may come back have us reluctant to go that route.

Your opinions and experience in similar cases are highly valued!

 

[MAPR-Austin]

Pictures will help a lot.

Are there any visible cracks in the grout or tile? What does the equipment room look like? Are the pipes for the pool copper or PVC (Plastic)? Are the skimmers cracked inside at all? Any big cracks in the decking, or obvious areas of water leakage from outside the pool area?

Have you had a leak location done on the pool?

If you have a beautiful and unique pool I would try to keep it that way.

 

[ajw22]

No pool is maintenance free.

Plaster pools need to be replastered.

Liner pools need replacement when they tear.

Tile pools need maintenance of the tiles and grout to keep it waterproof.

How long has it been since any maintenance was done on the tiles? Fixing small problems on a tile pool every year or two can keep it going for a long time. It sounds like you have catch up maintenance to be done.

 

[kimkats]

All of the above have some helpful info. I await your input on what they have said.

 

[oh_me_oh_my]

OK so more context. For general pictures, you can see my profile. I will grab pictures of areas of concern tomorrow.

In 2015, before we purchased the house, the pool was re-grouted with epoxy grout, and it appears that the tile in the shallow end was completely replaced.

We found out from neighbours that the previous owners had had some issues with water loss. When we purchased the house (2016) things were fantastic, no water loss.

Within about 1.5 years, we started to see some erosion of the grout in a few areas, and started to see some water loss - 1/2 to 1 inch a day. We plugged the skimmer, drain, and return, and still saw the same water loss. Pumped the pool down below the light, still saw the same water loss. Drained the pool entirely, cleaned the walls thoroughly, and repaired the eroded grout. Refilled, and the water loss was back to barely noticeable, but not gone.

Eventually the water loss came back, 1/2 to 1 inch a day.

Called a leak detection company, and they said the only thing they would do is come out and identify missing grout (which we had already done with a snorkel as well as draining).

We pumped the water down again (not fully this time), did more grout repair, the water loss slowed. Never really solved it. It is particularly bad in the spring and fall - we assume due to ground movement / water changes. We are on a bluff, but there are signs that the house has shifted in its lifetime.

Now, we most recently started seeing about 2 inches of water loss a day. This time we just let the water go down until it stopped - and it stopped just below / at the level of the shallow end and the standing ledge that surrounds the pool. We see more grout erosion than previous times - more than can be spot repaired.

This is where we sit today. I realize that grout and tile are not the waterproofing layer of a pool - although I see that epoxy grout providers do say that epoxy grout is waterproof. I suspect that the former owners re-grouted with epoxy grout, and refinished the shallow end, in an effort to solve their previous leak issues.

We refilled the pool with about an inch above the shallow end / standing ledge and let it settle. I have used food colouring to try and identify where any leak(s) might be, but it's not been conclusive so far. I will repeat it again with a bit more water (about 4 inches) so that the drops don't hit the bottom when they fall, so we can see better if there is any pronounced movement.

Summary:
- equipment room is fantastic, no issues. piping is water-tight
- pool had issues before we bought the house
- grout was eroding, we repaired it multiple times
- there are no missing tiles, any visible cracks have been repaired
- leak detection company said they would only point out missing grout
- water loss is back, and worse than ever before
- let the level go down, it stopped just below shallow end and perimeter standing shelf
- trying to do a dye test on our own

As I said, help and perspective is appreciated. I have been told that re-grouting won't solve this, but if it would, clearly that's a preferred option. Thanks all, again.

 

[Bperry]

OK so more context. For general pictures, you can see my profile. I will grab pictures of areas of concern tomorrow.

In 2015, before we purchased the house, the pool was re-grouted with epoxy grout, and it appears that the tile in the shallow end was completely replaced.

We found out from neighbours that the previous owners had had some issues with water loss. When we purchased the house (2016) things were fantastic, no water loss.

Within about 1.5 years, we started to see some erosion of the grout in a few areas, and started to see some water loss - 1/2 to 1 inch a day. We plugged the skimmer, drain, and return, and still saw the same water loss. Pumped the pool down below the light, still saw the same water loss. Drained the pool entirely, cleaned the walls thoroughly, and repaired the eroded grout. Refilled, and the water loss was back to barely noticeable, but not gone.

Eventually the water loss came back, 1/2 to 1 inch a day.

Called a leak detection company, and they said the only thing they would do is come out and identify missing grout (which we had already done with a snorkel as well as draining).

We pumped the water down again (not fully this time), did more grout repair, the water loss slowed. Never really solved it. It is particularly bad in the spring and fall - we assume due to ground movement / water changes. We are on a bluff, but there are signs that the house has shifted in its lifetime.

Now, we most recently started seeing about 2 inches of water loss a day. This time we just let the water go down until it stopped - and it stopped just below / at the level of the shallow end and the standing ledge that surrounds the pool. We see more grout erosion than previous times - more than can be spot repaired.

This is where we sit today. I realize that grout and tile are not the waterproofing layer of a pool - although I see that epoxy grout providers do say that epoxy grout is waterproof. I suspect that the former owners re-grouted with epoxy grout, and refinished the shallow end, in an effort to solve their previous leak issues.

We refilled the pool with about an inch above the shallow end / standing ledge and let it settle. I have used food colouring to try and identify where any leak(s) might be, but it's not been conclusive so far. I will repeat it again with a bit more water (about 4 inches) so that the drops don't hit the bottom when they fall, so we can see better if there is any pronounced movement.

Summary:
- equipment room is fantastic, no issues. piping is water-tight
- pool had issues before we bought the house
- grout was eroding, we repaired it multiple times
- there are no missing tiles, any visible cracks have been repaired
- leak detection company said they would only point out missing grout
- water loss is back, and worse than ever before
- let the level go down, it stopped just below shallow end and perimeter standing shelf
- trying to do a dye test on our own

As I said, help and perspective is appreciated. I have been told that re-grouting won't solve this, but if it would, clearly that's a preferred option. Thanks all, again.

The grout and tile IS the waterproofing layer in your case. The trouble may be that the leak has been ongoing for so long that the dirt under the pool shell is saturated and now allowing the pool shell to shift which causes more cracks, which causes more leaks and the cycle gets worse.

 

[oh_me_oh_my]

I'm getting (and reading) conflicting accounts of whether the tile and grout are just a cosmetic layer, or the waterproofing layer. It seems apparent to me that the areas of grout erosion are most likely due to water passing through the grout, and that the grout is a barrier, even if it isn't truly waterproofing. The pool builder we contracted explicitly stated that the grout is not the waterproofing.

The worst of the grout loss is isolated to a few areas, but has spread / widened over time as we have repaired the areas where we saw the erosion. Water loss has always lessened after the grout repairs, but we do see a change in water loss in the spring and fall typically (when we probably have some ground movement with runoff and freeze/thaw).

I would love for the solution to be either fully re-grouting the problem areas, or at worst removing the tile from the problem areas and repairing the shell behind them - but at this point it seems inconclusive that that will do what we need. Private concrete pools are a rarity in our area, so it looks like our options are limited for contractors.

 

[Bperry]

I'm getting (and reading) conflicting accounts of whether the tile and grout are just a cosmetic layer, or the waterproofing layer. It seems apparent to me that the areas of grout erosion are most likely due to water passing through the grout, and that the grout is a barrier, even if it isn't truly waterproofing. The pool builder we contracted explicitly stated that the grout is not the waterproofing.

The worst of the grout loss is isolated to a few areas, but has spread / widened over time as we have repaired the areas where we saw the erosion. Water loss has always lessened after the grout repairs, but we do see a change in water loss in the spring and fall typically (when we probably have some ground movement with runoff and freeze/thaw).

I would love for the solution to be either fully re-grouting the problem areas, or at worst removing the tile from the problem areas and repairing the shell behind them - but at this point it seems inconclusive that that will do what we need. Private concrete pools are a rarity in our area, so it looks like our options are limited for contractors.

It’s certainly possible that the builders put a layer of waterproofing membrane like hydroban under the tile before they tiled it but 50 years ago I’m not sure that even existed. But I am 100% confident that tile is waterproof and epoxy grout is waterproof. If water is getting through the shell into supporting soil, the soil movement can compromise the pool shell and cause cracks in the plaster/epoxy grout. If this is an indoor pool it’s especially concerning assuming the same soil is supporting your home foundation.

If it was my pool? I’d drain it completely (and remove the hydrostatic plug if it has one and if it doesn’t I’d drill a relief hole in the shell to prevent ground water from floating the shell since it sounds like there’s a decent amount of moisture under it. Then I’d remove all of the tile and assess what condition the shell was in and make any repairs necessary. Then you can either retile, plaster, or vinyl liner. But letting an ongoing leak continue to occur would not be something I’d entertain. I can show you pictures of what leaking water into the soil can do (because a leak was left ongoing so long), my pool is out of level about an inch and the decking sank 6+ inches and cracked the pool shell in several places. You can take a look at my pool renovation thread if interested.

 

[ajw22]

What format tiles do you have? Large format tiles are the best as they minimize the amount of grout lines while 1X1 tiles are the worst.

Tile and grout form the primary waterproofing barrier. For anyone that tells you different ask them what does the waterproofing if not the tile and grout?

I think removing all the tile is an extreme and expensive step that should only be done if it is clear there is structural cracking in the shell that must be repaired. Once the tile is removed I doubt it will be economical to replace it with tile at todays labor costs.

Show us some pictures of the pool and tile. And of the worst of the eroded grout areas.

 

[ajw22]

Construction methods for tile pools have evolved in the 50 years since your pool was built.

The waterproofing materials mentioned below were not available 50 years ago. The tile and grout was relied on for the waterproofing.

Have you seen down to the gunite under a tile to see what buildup In materials you have under the tile?

Here is the current recommended glass tile installation process from Oceanside Glass & Tile...

Glasstile

www.glasstile.com

https://cdn.shopify.com/s/files/1/0...l-Water-Feature-Installation.pdf?v=1625588595

 

[MAPR-Austin]

I'm getting (and reading) conflicting accounts of whether the tile and grout are just a cosmetic layer, or the waterproofing layer. It seems apparent to me that the areas of grout erosion are most likely due to water passing through the grout, and that the grout is a barrier, even if it isn't truly waterproofing. The pool builder we contracted explicitly stated that the grout is not the waterproofing.

The worst of the grout loss is isolated to a few areas, but has spread / widened over time as we have repaired the areas where we saw the erosion. Water loss has always lessened after the grout repairs, but we do see a change in water loss in the spring and fall typically (when we probably have some ground movement with runoff and freeze/thaw).

I would love for the solution to be either fully re-grouting the problem areas, or at worst removing the tile from the problem areas and repairing the shell behind them - but at this point it seems inconclusive that that will do what we need. Private concrete pools are a rarity in our area, so it looks like our options are limited for contractors.

Eagerly awaiting pictures.

In my experience the shell is typically 'water tight' and the plaster/tile surface is the attempt at making it 'water proof'. If you are losing 2" a day it is not a matter of just the missing grout, it is a matter of something going on with the shell underneath. You almost certainly have a crack in the shell, the re-grouting seals things up until the shell moves a little (likely with seasonal change as you noted).

Can you source replacement tiles? Once you find where the water is leaking from, you can chip the tiles off and do epoxy injection on the cracks, and then reset tiles over the area.

If you have a toe ledge around the pool, is the transition from the toe ledge to the wall a 90 degree angle? If so, the pool might have been constructed floor first, and then the walls poured separately. This method leaves a cold joint where the floor and walls meet - check this area well for leaks.

Use this for detecting leaks, it hold together underwater and works much better than food dye.

https://www.amazon.com/Detection-Concentrated-Perfect-Background-Complaint/dp/B07JW66D3Z/ref=asc_df_B07JW66D3Z/?tag=hyprod-20&linkCode=df0&hvadid=632245364777&hvpos=&hvnetw=g&hvrand=11223355817022669270&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9023158&hvtargid=pla-719960905428&psc=1&mcid=f9865172fb9f303aaeb40705d0971127&gclid=CjwKCAiArfauBhApEiwAeoB7qJGvnQMEKoPdBNrfwj2g8PssF0O7ZuhSZQKvcHEG24BSg2Y9BeqiKhoCpI0QAvD_BwE

 

[oh_me_oh_my]

Sorry for the delay, it's been busy. Updates:

- We found a pool contractor that also does leak detection as well as tile repair. They used a tool that had an outdoor (ground?) lead, a floating sender unit of some sort, and a pole mounted receiver with headphones.
- This identified multiple leaks, both in places we had previously repaired, as well as other places
- They also dye tested, and confirmed a few of the leaks.
- Independent of them, I purchased the dye test like the one linked on Amazon above.
- With the dye, I found what appeared to be a leak at a cracked tile, near a previous repair (a long step crack)

Before we purchased the house, it was clear that there has been some ground movement - likely due to the outside drainage. They had done some mitigation, but we will be completely fixing it, as we want to stop (or at least reduce as much as possible) any issues due to runoff. The (previous) movement is apparent in a repaired step crack in the outside brick of the pool enclosure that seems to be in a similar place to a step crack in the pool.

I have attached three pictures:
- one shows our step crack repair and some of the repaired grout on the standing ledge. Unfortunately that step crack goes over the ledge and down a few feet deeper into the deep end. The deeper part of this step crack was identified as a leak spot.
- one picture shows typical grout erosion in a random part of the pool. You can see a bit of previous repair with underwater epoxy (yes it is an ugly repair, that one was likely done while I was holding my breath).
- the last picture shows a void in the grout; however, using the better dye test, I did not see any water moving into that void

Regarding the standing ledge, the transition to the deep end is rounded / sloped, not a 90 degree. The transition at the wall base is 90 degrees as shown.

The pool contractor specializes in pool renovations, and indicated that they would be willing to repair the cracks, but that they are concerned about unidentified cracks, as well as any further movement / new cracks forming. As such, they have suggested going with a liner. They are going to quote a pool renovation including the installation of a liner, steps (we have a very deep shallow end with a ladder but no steps right now) a new skimmer (to work with the liner) and replacement light.

We are definitely seeing seasonal effects - the weather has been very up and down (from warm spring days back into snow and cold). I added water for the leak detection, and it immediately went down at least an inch overnight - but now it seems to have stabilized again. I'm sure there is some sort of equilibrium with the ground water, as well as general ground movement, going on. The pool contractor reassured us that the shell is structurally sound even if it is no longer watertight, as there is no lifting or large cracks.

Thanks all for your help - if you have ideas / suggestions / things to watch out for, it is greatly appreciated.

 

[kimkats]

While I LOVE a tile pool I love a pool that holds water even better so...............I would go with a liner and save up your pennies until you can afford to retile it again.