Thoughts on condition of pool plaster and mortar cracks

[Fluorescent_Frogs]

Hey all,

I have these cracks around the edge of my pool, and also worn areas in the plaster.

The pool is about 13-14 years old, I’ve owned it for 4, and been taking care of it myself for just the last few months.

Looking for honest feedback about how bad (or not) the plaster looks, and how much time I may realistically have before a replaster. I am in central Texas. (And yes I notice some little green algae areas in corners despite scrubbing and keeping the chlorine at 10 )

For the mortar crack, if I were to redo this myself, is the best bet to remove the existing and put in new sealant? If so, what product is recommended? (Or, is it fine and I don’t have to worry about it?)

Thank you!!

 

[ajw22]

That is your expansion joint. The old mastic needs to be scraped out, and then foam backing rod and Deck-O-Seal or Sikaflex 1A should be put on top of it.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

DECK-O-SEAL - Polysulfide-Based Joint Sealant

Seal all cracks and joints with DECK-O-SEAL two-part, elastomeric, polysulfide-based joint sealant. DECK-O-SEAL is used for caulking and sealing joints subject to concrete movement to provide a firm, flexible, weather-tight seal. It is ideal for sealing joints around swimming pools, and for...

www.deckoseal.com

(And yes I notice some little green algae areas in corners despite scrubbing and keeping the chlorine at 10 )

What is your CYA?

Your stains can be organic.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Stain ID Kit | Jacks Magic

jacksmagic.com

Plaster Installation and Maintenance - Further Reading

www.troublefreepool.com

You will get more views if you post your pictures to the forum.

Picture Posting and Resizing - Further Reading

www.troublefreepool.com

 

[Fluorescent_Frogs]

That is your expansion joint. The old mastic needs to be scraped out, and then foam backing rod and Deck-O-Seal or Sikaflex 1A should be put on top of it.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

DECK-O-SEAL - Polysulfide-Based Joint Sealant

Seal all cracks and joints with DECK-O-SEAL two-part, elastomeric, polysulfide-based joint sealant. DECK-O-SEAL is used for caulking and sealing joints subject to concrete movement to provide a firm, flexible, weather-tight seal. It is ideal for sealing joints around swimming pools, and for...

www.deckoseal.com

What is your CYA?

Your stains can be organic.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Stain ID Kit | Jacks Magic

jacksmagic.com

Plaster Installation and Maintenance - Further Reading

www.troublefreepool.com

You will get more views if you post your pictures to the forum.

Picture Posting and Resizing - Further Reading

www.troublefreepool.com

Hi there! Thanks for the great info. Replacing the mastic seems time consuming but not altogether difficult so that’s good.

My CYA is generally 60-70. The stains only seem to appear in the corners.

Thank you for the link to resize photos - was able to add them into the post itself now.

 

[ajw22]

You need to follow the SLAM Process to get rid of your algae problem.

Algae Archives

www.troublefreepool.com

 

[Fluorescent_Frogs]

You need to follow the SLAM Process to get rid of your algae problem.

Algae Archives

www.troublefreepool.com

Thank you, I’ll do that.

Do you think the plaster in the pool looks fine? Certainly worn, but still ok?

Thanks

 

[ajw22]

Do you think the plaster in the pool looks fine? Certainly worn, but still ok?

If the pool is not leaking water, the plaster is fine and doing its job.

Get rid of your algae problems, as some of the stains can be organic. Then run through the stain ID process and report your results.

 

[JamesW]

The plaster looks like copper stains.

Drop a vitamin C tablet on a spot to see what happens.

The expansion joint looks like it was grouted and not filled with sealant.

It it grout or sealant?

The pool looks like it has raised or the deck is settling.

 

[Fluorescent_Frogs]

The plaster looks like copper stains.

Drop a vitamin C tablet on a spot to see what happens.

The expansion joint looks like it was grouted and not filled with sealant.

It it grout or sealant?

The pool looks like it has raised or the deck is settling.

The expansion joint seems to have a layer of sealant on top (it’s rubbery, moves when I apply pressure), but below that, it seems to be grout, same hardness as the grout between the tiles in the coping. There are also a few cracks in the pool deck starting from beside the coping, but I’m not sure how long those have been there.

Interestingly, there seem to be three different kinds of materials there - closest to the stone coping there looks to be a silicone looking one (tan color), but it’s not everywhere, then there is the brown one that’s cracked which seems like sealant, then closest to the pool deck, under the brown sealant, is a slightly whiter one which is hard like grout or mortar. So I’m not really sure what is going on, if the coping was at the same level as the pool deck at one point… no idea.

I haven’t drained the pool or anything. However in Austin lately we have had a bad drought, punctuated by very heavy but infrequent rains.

 

[JamesW]

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[Fluorescent_Frogs]

I had a concrete/pool repair company come by today to give me a quote to replace the expansion joint around my pool. The sealant there right now is cracked, and I think the deck has settled on one side, causing the crack in the sealant between the deck and the coping. It looks like there are currently two layers of SikaFlex or some similar compound (hard, but also flexible - not like mortar).

The guy I had come out today said they would use a silicone, not a polyurethane sealant, and said it would last 20 years. They offer a 5 year warranty for cracks. BUT, he wouldn't remove the old stuff! Just layer it on top. When I expressed concerns about the adhesive quality, he said it would be fine. He said it would be too hard to remove, and they don't want to damage the deck or the coping by using a grinder to it. I also don't know how good that would look, to just have silicone on top of whatever is there now. From reading other posts here the consensus seems to be to remove what's already there, then add backer rod and new Sika or Deck o Seal. I will say my coping and deck are no longer level with each other so maybe that makes a difference? He quoted around $750 to do around half the pool (the other half is a raised waterfall part with plants behind it). But again, they're not removing the old stuff.

Could really use some insight into this from folks who know more, have done this before, and/or have seen silicone being used. I'm suspicious of not removing the old material, but could use some more opinions.

 

[JoyfulNoise]

That deck has settled a lot.

Are you sure it's done settling?
Do you have insights into why it settled?
Was there a leak? Is there still a leak?

I would want answers to those questions before dropping any cash on fixes that likely won't work or that more settling (or heaving) will cause damage too. My guess is that this guy you brought in for an estimate will absolutely "warranty" his work ... and then deny any warranty claim because your deck is sinking and that's not the fault of his workmanship ...

 

[Fluorescent_Frogs]

That deck has settled a lot.

Are you sure it's done settling?
Do you have insights into why it settled?
Was there a leak? Is there still a leak?

I'm not sure of those, to be honest. We've been here about 4 years, and it's settled since then, but it appears there was some settling going on before too. (They redid that sealant, and there were some cracks in the pool deck even at that time which have gotten worse). We have a drainage thing under the deck which may be leaking, or maybe the ground is shifting or drying, I'm really not sure to be honest. Maybe squirrels? Our driveway is also cracking. We had to get half of it jacked up with foam in 2021, now the other half is sinking. :/

 

[JamesW]

Thoughts on condition of pool plaster and mortar cracks

Hey all, I have these cracks around the edge of my pool, and also worn areas in the plaster. The pool is about 13-14 years old, I’ve owned it for 4, and been taking care of it myself for just the last few months. Looking for honest feedback about how bad (or not) the plaster looks, and how...

www.troublefreepool.com

 

[ajw22]

That is not your typical expansion joint repair with the heaved deck. Your contractor does not want to open up a can of worms by removing the existing material. And that gap looks wider and deeper than a typical expansion joint that can be filled with foam backer rod.

We have seen many threads about folks in your area having unstable soil causing cracks in the pool and deck. You have an underlying ground condition that some silicone is not going to fix.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

 

[JoyfulNoise]

I'm not sure of those, to be honest. We've been here about 4 years, and it's settled since then, but it appears there was some settling going on before too. (They redid that sealant, and there were some cracks in the pool deck even at that time which have gotten worse). We have a drainage thing under the deck which may be leaking, or maybe the ground is shifting or drying, I'm really not sure to be honest. Maybe squirrels? Our driveway is also cracking. We had to get half of it jacked up with foam in 2021, now the other half is sinking. :/

It sounds like your property has some serious geotechnical issues with the soil. A lot of areas in Texas are known to not have good soil to build on - either very expansive clay soil or soggy swamp soils. Good construction practices call for soil analyses and remediation prior to building anything. If you did not build the pool, then it's hard to say what the builder did ... and they may have done nothing at all in terms of foundation stabilization for the pool or driveway (homebuilders tend to be a little bit better because they are easier targets for liability lawsuits).

Generally speaking, silicone and polyurethane are incompatible unless they are formulated to work together. In your case, old dried out P/U is unlikely to be a good substrate to work on and so I would expect the silicone to not last long or to delaminate. The entire expansion joint needs to be cleaned out. The flexible layer you mentioned might actually be asbestos foam barrier or some other foam barrier material that is typically used to create a slip joint between cement surfaces. It would be similar to using backer rod. The right way to do it is as you have discovered - clean out all the old junk, apply a backer rod, and then fill with a flexible joint compound. You can sand the surface to give it a more natural look to match the coping and deck.

Any fix is going to be temporary based on the movement of that deck. Should it settle more or heave with changes in moisture, then you're likely going to see any joint crack. Also, if the vertical displacement is too great, you won't get a clean joint between the two surfaces as the material will slump under gravity while it is curing.

 

[Fluorescent_Frogs]

That is not your typical expansion joint repair with the heaved deck. Your contractor does not want to open up a can of worms by removing the existing material. And that gap looks wider and deeper than a typical expansion joint that can be filled with foam backer rod.

We have seen many threads about folks in your area having unstable soil causing cracks in the pool and deck. You have an underlying ground condition that some silicone is not going to fix.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

Do you think that getting the deck foam jacked is the best solution first, before addressing the expansion joint? The gap is quite large. Probably 1/2 - 3/4" wide in some places. And vertical displacement is probably up to an inch between the deck and the top of the coping stones. I'm sure the drought we've been having in central Texas hasn't helped, followed by the deluges of rain too.. Certainly want to avoid cracks in the pool itself.

It sounds like your property has some serious geotechnical issues with the soil. A lot of areas in Texas are known to not have good soil to build on - either very expansive clay soil or soggy swamp soils. Good construction practices call for soil analyses and remediation prior to building anything. If you did not build the pool, then it's hard to say what the builder did ... and they may have done nothing at all in terms of foundation stabilization for the pool or driveway (homebuilders tend to be a little bit better because they are easier targets for liability lawsuits).

Our roads near our house are also cracking quite a bit. The house is from 2004, and the pool from 2010-2011 ish. A garage addition and new driveway added in 2014. So I'm not sure what they had done for the soil, but things have definitely settled. Thankfully no cracking inside the house, no cracks in the drywall as far as I can tell.

Generally speaking, silicone and polyurethane are incompatible unless they are formulated to work together. In your case, old dried out P/U is unlikely to be a good substrate to work on and so I would expect the silicone to not last long or to delaminate. The entire expansion joint needs to be cleaned out. The flexible layer you mentioned might actually be asbestos foam barrier or some other foam barrier material that is typically used to create a slip joint between cement surfaces. It would be similar to using backer rod. The right way to do it is as you have discovered - clean out all the old junk, apply a backer rod, and then fill with a flexible joint compound. You can sand the surface to give it a more natural look to match the coping and deck.

Thank you, this is what I thought. Having done lots of other home renovations myself this was my gut feeling, but the pool repair guy was so confident the silicone would work that he didn't even really explain WHY it would be the best in his opinion.

Any fix is going to be temporary based on the movement of that deck. Should it settle more or heave with changes in moisture, then you're likely going to see any joint crack. Also, if the vertical displacement is too great, you won't get a clean joint between the two surfaces as the material will slump under gravity while it is curing.

That's what I thought. Sad
The vertical displacement on one side of the pool is close to an inch, whereas near the spa it's less, maybe 1/4". Really noticeable on the other side. If I replace the joint myself, I was going to use Sika but not the self leveling one (I think there is SL and non SL, could be wrong), because of that vertical displacement. I'm not quite sure where to start with assessing this - a company to raise the deck and jack it with foam? I don't even know how/if a person remediates soil settling generally... Sounds like major $$!

 

[JoyfulNoise]

The deck is placed so soil remediation is out of the question unless you demolition the deck and redo it. That's going to be a huge investment. You can bring in some companies that do mudjacking or foam jacking and see what they say. How long that will last is anyone's guess. You said the driveway got foam-jacked at one point so you might get that contractor's opinion on the pool deck.

 

[Fluorescent_Frogs]

The deck is placed so soil remediation is out of the question unless you demolition the deck and redo it. That's going to be a huge investment. You can bring in some companies that do mudjacking or foam jacking and see what they say. How long that will last is anyone's guess. You said the driveway got foam-jacked at one point so you might get that contractor's opinion on the pool deck.

Yeah, that's a good idea. Thanks for your help and insights!

 

[ajw22]

Glad we can help.

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[Bperry]

Yeah, that's a good idea. Thanks for your help and insights!

I can say if there was a water leak that may have caused some of the settling and then water getting into joints could be causing further settling.