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Easy Fixes For Concrete Pool Problems

Easy fixes for concrete pool problems
What would you say if I told you that some of the most expensive and most frustrating damage and repairs that you can need to do to a concrete pool could largely be avoided with extremely simple steps that anyone can take? I bet you think that sounds like an exaggeration. Concrete pools as we all know are very expensive to maintain (not entirely true) and there is no getting away from expensive tile repairs or new plaster surfaces for your pool. Or is there? Something that I see with shocking regularity with concrete pools, especially older concrete pools, are totally preventable problems that are being ignored.

Concrete pools are a pool system. If you think about this it makes sense since concrete is not waterproof in the slightest. How do you get the pool to hold water, and not leak, and not have that leaking water damage stuff? The way is by having a concrete pool system. As much as it seems like you have decorative or cosmetic parts to your pool like the tile band, or the coping on top of the pool wall, these are parts of the total pool system. In reality they are here to perform a specific function as part of the concrete pool system and they are not just there for the pretty looks. If you built a pool but just simply did not install the coping, how long do you think the tiles would last before they started falling off? The answer is not very long at all. So how can you apply this information to your swimming pool? Very easily actually, and this is something that every pool owner can inspect for themselves.

expansion gap between pool coping and deck Expansion gap between the coping and the deck

Your pool deck is made from concrete, stone or something similarly hard. Concrete for example will expand in size by up to 1/2" laterally when exposed to 100 degree F temperature variations. Blazing hot summer sun compared to cold season middle of the night will get close to this differential for most swimming pool owners. This is why you must have a gap in between your pool deck and your pool coping. The coping can not move. It is attached to the pool wall which moves independently from everything else in the ground. If you did not have this expansion gap then the deck would expand and push on the coping and the coping would push on the inside wall of your pool, which would crack lengthwise. This is called deck shear and definitely something you want to avoid. You avoid this by having an expansion gap in between the coping and the deck.

Deck O Seal
Where concrete pool owners will go wrong with the expansion joint in between the deck and the coping is that over time this joint will fail. It is exposed to a lot of temperature fluctuation, direct sun, chlorinated water from the pool...it is a very tough environment to exist in. As the urethane material is exposed to UV and chemicals over time it will lose elasticity and become brittle. It will crack, create gaps and fall out. When this happens you need to fix it right away. This is not the kind of repair that you notice and then get to the following spring. If you own a concrete pool go walk the perimeter right now and inspect this joint for deficiencies of any kind. Spot repairs should be made with the same material used the first time, often a product called Deck O Seal. If you don't know what was used or can not find deck-o-seal then a concrete urethane product like NP1 would be my second choice. If you see a small failure repair this important expansion joint right away. If you see multiple failures then it might be time to have the entire expansion joint material removed and reset. This simple joint is responsible for more tile and plaster failures in concrete pools than any other thing I can name. Definitely low hanging fruit that all concrete pool owners should be all over from a maintenance perspective, assuming you knew how important this little detail really was. Now you do.

joint failure between tile and coping
Expansion joint between tile and coping

In a very similar sense to the coping and deck joint, there is a similar situation happening on the underside of the coping where the top of the tile meets with the bottom of the coping cantilever. In this case we are not worried about horizontal pressure from expansion as much as we are protecting a known weak area. When you have a hard surface like concrete, tile or stone and you want to transition planes to another hard concrete, tile or stone surface, you can not make this transition with a third hard material like grout. All too often, even with concrete pools still being installed today, installers put grout in between the top of the tile and the underside of the coping. This is a guaranteed failure point and if you have this current arrangement in your pool then a close inspection should reveal that grout joint has cracked in its entirety, and even many places will have had grout fall out from this location. You might have even hired someone to reinstall that failed grout joint and wouldn't you know it has started failing again!

Polyurethane Sealant
You might be wondering why the company that built your pool did it wrong and used grout instead of a flexible urethane for transitioning planes between your tile and coping. You might also wonder why all of the people who have worked on your pool have not mentioned this, and when you hired someone to put the grout joint back they didn't mention anything to you about needing a flexible joint in this location. I do not know what to tell you there...I also wonder why people who work on pools for a living do not understand basic functions of how the pool should work. Ultimately you need to take control of the situation as you are the one paying all the bills when things break. Now that you know you need something like a gun grade Deck-o-seal bead in between your coping and your tile you can requisition this work from a local installer or even do it yourself however be warned it is much harder than it looks to make this bead look good with urethane. It's like silicone on steroids, is hard to work with, and sticks to absolutely everything. Along these lines, silicone is definitely not the right product for this joint, or any expansion joint on a concrete pool. It is too light duty and water sensitive for these applications.

why you should not acid wash your pool
Acid washing your pool plaster

Buckle your seatbelts because I am about to blow your mind. Did you know that you are not supposed to acid wash a concrete swimming pool...like ever? Acid washing pools is as common of a service as a filter cleaning or new pump seal. Unfortunately this is 100% counterproductive to the longevity of your pool interior surface. When you install a plaster surface in a pool it is supposed to be as smooth as silk. Rub it with a paper towel and it should not rip up the towel. Now compare that finish to what many concrete pool owners have which is a finish so rough that your feet are bleeding and your swim suit is torn to shreds. As pool plaster gets older it still looks the same. This is how concrete pool owners often end up going too long before getting a new surface installed. In a vinyl pool you replace the surface because the old one has holes and won't hold water. In a concrete pool you replace when the surface feels rough. When you acid wash a pool surface, or any concrete surface, you are burning away the top layer of portland cement and leaving behind the exposed sand. Essentially you are making exposed aggregate concrete only using sand instead of colored stones. In essence, you strip away years of life from the plaster in one fell swoop. It looks clean and new for sure. You have burned it to a radiant, sparkling shine.

This is why pool owners ask for this service. They think it makes the pool look great. It does, at the expense of 30% or more of the service life of your plaster. You don't have to believe me, in fact I insist you do not. Please pour some test patches of concrete and make them as smooth as you can. Like plaster, make it as smooth as you can is only a few quick passes and then let it set up until it starts to haze (water absorbs, less glossy) and then hit it with a sponge float and your trowel up hard on its edge. This is the hard trowel finish. let it cure to hard. It should be smooth enough to rub it on your face. Now acid wash it. What does it feel like now? Not so smooth is it? The stronger the acid concentration the more aggressive the burning effects on the portland layer.

When you acid wash a color plaster pool the acid wash should be so weak it does not bubble at all. It is 95% hard scrubbing with brushes that clears the cement haze and exposes the color in the aggregate without making the plaster rough. Acid washing with stronger acid is waaaaay easier. It takes hardly any brushing at all, just push the acid around and let it bubble and hiss. Everywhere it touches has bold and bright colors, or if you are cleaning a stained green pool the plaster will look brilliant white and new again. It is anything but new. Acid washing your pool is not something you do to make it look good. It is supposed to be a last resort for specific situaitons like a color plaster that the customer does not want to wait three years before they see the color they paid for.

If your pool is green then chemically treat it, and vacuum and brush daily as well as making chemical corrections as needed to make the water sanitary and perfectly balanced. Almost all staining can be resolved in concrete pools by prolonged periods of time of proper water chemistry combined with specific treatments as needed for stains in the plaster. If your plaster is so porous that you can't get rid of the stains you need a new plaster, not an acid wash which will only serve to make an already bad situation worse for you. If you are a concrete pool owner that acid washes their pool regularly I would encourage you to stop this destructive process and you can learn more in this article about acid washing concrete pools.

Concrete pool maintenance is incredibly important. Failure to maintain key elements of your pool can result in systematic failure of expensive, integral components of your pool. As a pool owner and the person responsible for the repair bills the onus is on you to educate yourself about how to care for your pool properly. Not all pool professionals will approach maintenance for a concrete pool with the same level of experience, care and mindfulness of longevity and accepted construction practice as you are reading on this page. It takes a lot of experience to know how to build a quality concrete pool, and to know how they tend to leak and fail, so you need to decide for yourself as a pool owner what sounds like prudent advice and what does not. If acid washing does not make your pool plaster rough then you will have no problem recreating these results for yourself. When you have tiles that fall off do you see a problem with the flexible urethane joint above the tiles (missing) or is the expansion joint at the deck / coping junction compromised or missing in this particular location? Don't let someone else's lack of experience cost you extra money with your concrete pool repairs in the future. Follow the easy steps on this page and your pool system will look better, last longer and most importantly operate cohesively as a proven system.

Common problems with concrete pools

How to fix tiles in a concrete pool

Why you should avoid acid washing your pool

How to repair cracks in a concrete pool

New pool owners fast facts

How to make you pool last as long as possible

8 Part series on how to inspect a concrete pool

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