Deep cracks along top edge of concrete pool

[proto17]

My 40,000 gal pool has been shedding tiles in the deep end for the last two years. We've just been collecting the pieces until last weekend when we decided to start chipping away at the old lose and cracked tiles (hoping to replace the tiles). What we found were some really deep cracks. The main crack runs approx 10-15 feet in total. As we were chipping away at the tiles, the concrete (or is it gunite?) was coming off in large chunks with the tile (still attached).

Last year I looked up a method of repairing cracks that used some kind of expanding goop that was injected via "ports" (holes drilled in the pool):

But that method would seemingly not work for a crack this high up on the pool.

Question is: Is this a problem that could be done without spending thousands on a pro repair? We had someone come out last year and they quoted at *least* $6,000 to remove all the tile and start over. I'd rather slowly fill the thing in than spend that much money on a crack

Here's a couple of videos:

Thanks in advance!

-Dave

 

[ajw22]

Welcome to TFP.

I don't think there are any tricks for low budget repair of cracks like that. We hate to see pools buried.

@bdavis466 @jimmythegreek can this pool be saved at an acceptable cost?

 

[bdavis466]

You're basically in the same situation as this guy:

Bond beam repair

I recently purchased a house with an in ground pool where the tile was loose around 1/3 of the pool, and a lot of the coping sounded hollow. After removing all of the tile I discovered bond beam damage in several places. As such, I have removed the coping stones, and chiseled out the bond beam...

www.troublefreepool.com

There's a good deal of great advice from some extremely knowledgeable people (really good looking too).

Notice that your horizontal crack is about 4" down from the top of the coping, your concrete deck is about 4" thick and there doesn't appear to be an expansion joint in place. Even if there is it probably doesn't extend all the way down to the gunite below the coping. When the deck expands from the heat of the day or any ground movement it puts pressure on the shell and transfers that force through the bond beam.

Take a look at the precast coping section:

Expansion Joints and Coping

Expansion joints – or more appropriately called isolation joints – are an essential part of constructing a structurally sound pool and deck. Concrete (and other similar decking options) expand and contract with changes in temperature which make an expansion joint necessary to prevent the deck...

www.troublefreepool.com

 

[proto17]

Thank you very much for the links! I had no clue how everything was constructed. Really helps to see the diagrams! There is an expansion joint, and the previous owners of the home said that we had to make sure to re-caulk with self leveling caulk each year. The caulk in the joints looks really rough, and we didn't do anything last year (unable to find a local source for the white self leveling, outdoor rated caulk), but the issue with the tiles has been since I bought the house a 2-3 years ago. So, all that is to ask if the caulk wasn't doing it's job, letting water into the mortar bed, and then freezing in the winter? We also noted that the pool would lost water a lot faster than expected if you filled it up to ~ 2/3 up the tile. Once the water was below about 1/3 then the water level would stay stable. I assume that's due to water leaking out through those massive cracks under the tile?

Looking at the other posts makes me better understand why we were quoted with removing all of the tile and starting over. Perhaps they were planning on re-doing all of the concrete at the top? Is this something that could be addressed just in the affected areas or does it really have to be done to the whole pool?

Thank you very much!!!

-Dave

 

[bdavis466]

You don't have to do the whole pool but it's not much more work and would prevent having the same issue again.

Just because you see the caulk between the deck and coping doesn't mean that the expansion joint goes all the way down to the gunite shell. My guess is the deck is directly in contact with the gunite below the coping and the expansion joint that you are seeing isn't really doing anything because it's not truly an expansion joint.

Unfortunately there isn't really an easy way to find out without doing a little bit of demolition but repairing the tile without addressing the issue is just pushing your current problem down the road.

 

[Winger 03]

So it appears a replacement of the coping is in order to properly address this - is that right Brian?

 

[bdavis466]

So it appears a replacement of the coping is in order to properly address this - is that right Brian?

I believe so.

You could try to dig out the expansion joint and see if its free the entire height of the deck. If it is then your freeze damage suspicion could be valid but I really doubt that's the case.

 

[proto17]

Would that just involve scraping out the caulk in a small section, perhaps blowing debris out with an air compressor, and then I *should* be able to see a gap in the two concrete sections (pool vs deck slab)? Maybe run a wooden dowel between the two to verify a gap in the event that it's hard to tell due to dirt?

 

[proto17]

Also, understanding that it's always better to go with the proper fix that will last: Are there options for packing the voids with some form of sealant and re-tiling? I don't like the idea of a shoddy repair, but I can't handle a bill in the thousands at this time I'm hoping for something that kicks the can down the road for this pool season, but does not do more damage than has already been done. Purpose being to allow a correct repair to be done once funds are available for such work (hopefully fall / winter).

 

[bdavis466]

That should work

 

[proto17]

I really appreciate the time and input, and completely understand that the path I am planning to take isn't the correct one. It's just the only one that I think I can financially accept at this point

Thankfully we have quite a lot of spare coping from the previous owner, so that won't be too bad to replace later.

 

[jimmythegreek]

I agree with brian the issue likely originated from the deck expansion. Water getting in and the winter just helped it break down. I'm not one to suggest rigging things but if you wanted to buy a year out of it you may be able to clean the cracks up and get it packed with cement and then thinset tile over it. Its not gonna last long term. If other areas are ok a similar tile and a patch may buy a season. Having extra coping helps amd if the beam is inside the deck under coping you would minimize disturbing the deck. Only issue I see is not damaging plaster. It's hard to take tile off and not chip plaster you have to diamond wheel a line under tile to get a clean break away

 

[proto17]

Jimmy,

Thankfully the tile is made of 5 different sections that are connected via a mesh with grout between each part. That makes them chip away in sections really cleanly. The bottom end of the tile is mostly okay. We are trying our best to not chip away that part for the very reason you stated. But, I had not thought about using a diamond cutoff wheel. I've been really worried about using powertools for this due to the risk of dropping them into the pool.

I'd love to drain the whole thing and work on it from the inside, but that's a decent chunk of change to fill the pool back up. Plus, I'm terrified of the possibility of the pool cracking due to the water table raising it up. Not sure if that's a real chance, but it's still scary. I live on land that used to be a farm, and the soil here is basically sand. I think that's why (at least according to the previous owner) the walls of the pool are a foot thick. Maybe that's normal? Just seems like a mitigation strategy for the shifting soil. Though, things may get a lot more solid as you dig down as far as the pool is.

-Dave

 

[jimmythegreek]

you should always use a GFCI extension cord when working around a pool, its an OSHA requirement. I would take the chance of not doing a relief cut and chipping them out manually, chances are ones gonna let go

 

[proto17]

Jimmy,

Good point about the GFCI! Thankfully all of the outlets that I can get to from the pool are GFCI protected. Might have to make some kind of float to catch things that get dropped just in case. Even though I will be fine if the tool falls in the water, the tool likely won't be

Which reminds me, what's the best way to remove the excess mortar from the concrete so that I can eventually put tiles back on? Using a hammer and chisel is pulling out really large chunks and is a pain in the butt. Is there a grinding attachment that works well? Was considering an air chisel, but I think that's going to make it really easy to take out too much concrete by mistake.

Thanks!

-Dave

 

[jimmythegreek]

a diamond cup wheel on an angle grinder. dont sweat making a mess, just get the work done and clean it up in one fell swoop later. a piece of 1"rigid insualtion is what I use for a catcher in the pool, duct tape it in place so its below where your working it will catch the majority of stuff falling. you have a concrete pool so no worries of damage, i mainly do liner pools so were careful. they sell GFCI extension cord whips that are like 3 feet long at big box stores, worth the 25 bucks to stay safe. We do work like this from inside the pool, if its cold somebody has a wetsuit on and is in the pool, if its deep wear a life vest and float and work, with a concrete pool you can put a ladder in the pool too

 

[proto17]

Huh, I wouldn't have thought of actually getting in the pool with the tools was normal thing. Makes me wonder though, have you ever tried using an air powered grinder for this kind of work? For me it seems safer, but maybe under powered.

 

[bdavis466]

Air tools work well around water and even under water. Don't expect them to last though?

 

[jimmythegreek]

We sure do. If I could dig up some of the pics of the ridiculous stuff we do to get access on the water side you would think were nuts. We've worked out of excavator buckets, inflatable rafts amd boats, I even repaired and caulked tile and coping in a guys kayak in cold weather. Gotta do what it takes some tools just take longer do whatever makes you feel safer

 

[proto17]

Wow, I really like the mental image of sitting in an excavator bucket

We just got a quote for ~ $10-12k to have all of the tile and coping removed, footing repaired, and all put back together. This place stated that they do not do repairs, and only do renovations. Hoping to have another company out today or tomorrow. Seems that there are a lot more places for renovation than for repair. Makes sense as you get more money =\ Just a whole lot of money for about 6 feet of problem

Do the air tools just not stand up to the same kind of abuse? In my head it seemed easy to use an air powered die grinder to work through the finer details / take care of high spots. I've never tried using air tools on concrete though. Definitely seems safer. A GFCI protected outlet will save me, but the tool will be rather unhappy about being in the water.

Does a normal 4 1/2" electric grinder do the trick with concrete? The tile is 6" high (my assumption) so much more seems like it would be too much. I've used death wheels a fair bit for metal and they have quite the kick when the bind. Is concrete a little more forgiving with binding up (and using a diamond cup wheel)?