Pool Step Repair
A very common problem that concrete pool owners will encounter is early and repeated failure of the steps in their pool and most specifically the top step. This does
not apply to all concrete pools however the area that I am most familiar with, the GTA location in Ontario Canada, has a serious problem with concrete pool steps.
There are a few factors at play here with one being that there are not very many concrete pool companies in this area, and another main reason being that Ontario
winters are very long and very cold. It may come as a surprise to some people familiar with concrete pool installations that over 90% of concrete pools in Ontario
have a painted interior surface. That is not a misprint. If you do not understand the significance of this statistic then all you need to know is that most concrete
pool experts agree that you should never paint a concrete pool.
If you are not "supposed" to paint a concrete pool, according to the people who know concrete pools the best, then why are so many concrete pools in Canada painted? The answer is simply because the people who know concrete pools the best are not located in Canada. What Canada does have however, is a very dense concentration of vinyl liner contractors and retail stores. This results in vinyl pool technicians crossing over into concrete pools. There are no vinyl pool installers crazy enough to take on a full pool plaster installation on a concrete pool, and if they did try, the results would almost certainly be a disaster. Plastering a pool is something that takes a team of experienced finishers and no amount of unskilled labor can make up for the lack of trowel experience. When a vinyl liner company decides to take on a concrete pool renovation, they will almost always recommend to paint the interior surface...simply because there are not very many alternatives. There are some newer roll-on interior surface "plaster" products, as well as the potential to subcontract installers such as Pebble Tec who are now active in Canada, however the quick in-and-out nature of painting a pool can be too tempting for some companies to pass up.
Part of the problem is the lack of skilled and experienced concrete pool companies in Ontario Canada. There are a few, but nothing compared to the thousands of vinyl pool contractors and companies. Since the average pool owner knows nothing about how the swimming pool industry is structured, what happens is that a concrete pool owner can end up calling dozens of pool companies only to be repeatedly told that they do not service concrete pools. This can result in the customer getting more persistent, and lowering their expectations from their hired contractor. Many times a vinyl pool company may attempt to pass on the work, knowing that concrete pools takes specialized training, but if the customer is persistent enough they may take the contract. Without specific experience in concrete pool construction and renovation, you will end up with problems like the one pictured above...deteriorating pool steps, specifically the top tread.
Why Does The Top Step Fail?
This question has a surprisingly simple answer - the step is not finished correctly. There are some areas where you may be able to get away with plastering the treads
of your pool steps, but in the harsh winter climate in Ontario Canada the top step experiences the worst possible climate conditions. Since swimming pools in Ontario
Canada need to be winterized, and part of this process includes partially draining the pool, the top step of the pool is usually left exposed above the water level.
The water actually helps to protect the interior finish of your concrete pool during the winter. Combine this with the horizontal surface of the top step and you have
a situation that is sure to result in early failure of the step.
The interior finish of concrete pools needs to be covered by water to protect it. Since the interior surface plaster layer is mechanically bonded to the substrate shell, there is concern for delaminating as a result of different rates of expansion and contraction. In most concrete pools in Ontario this amounts to noticeable crazing and surface cracks of exposed plaster on the pool walls, however the vertical nature of the surface is optimal for resisting freeze and thaw damage and minimizing delamination. The top tread of your pool steps is not so lucky.
So is the answer to refill your concrete pool after you winterize it? Not necessarily. While some concrete pool owners swear by minimizing air exposure on their interior surface, and they may be right, the reality is that most concrete pool owners in this area do not refill the pool after winterizing. To me, this would be like taking an asprin because you have a rock in your shoe...sure it will help, but why not address the problem specifically? The top step of a concrete pool in a cold climate location should not be plaster or painted - it should be tiled.
Tiling The Top Step Of Your Pool
If you have a concrete pool and you are located in an area that has sub zero winter temperatures then you should have the top step of your pool tiled. In theory, you
could even tile the horizontal surfaces of all of the step treads to keep the look consistent. At minimum you should have the top step of your pool tiled with a
commercial grade, matte (non slip) tile. Porcelain tiles are much, much stronger than ceramic tiles and you should look for a freeze rated tile specifically for this
For tile to be freeze resistant it needs to be installed in a very specific way, which includes using a waterproofing layer like Laticrete Hydro Ban. This is a roll on membrane substrate treatment that will create a waterproof layer that is suitable for tile installation. Could you just use regular modified thin set? You could, but it will fail early compared to how long tile will last when it is set correctly for the application.
Regular thin set products are porous, as is the concrete shell of your pool. What this means is that if you were to set tile on your pool step water will still be able to leach into the shell of the pool through the tile grout joints. While tile that is set without a waterproof membrane may still likely last quite a few years before failing, if you take the time to make a waterproof layer before setting your tile then you will probably never need to revisit this issue.
Once you have set the Hydro Ban waterproof membrane you then need to use Laticrete 254 Platinum to set the tile. Modified thin set like you can buy from your local hardware store is heavily modified and very impressive when it comes to bonding to multiple surfaces. The top step of a concrete pool in a cold climate application is essentially the holy grail for difficult conditions for tiles to endure. If you want to fix your tile steps properly, use the right products and get the results you are looking for.
Your tile installation is only as strong as the weakest link in the chain. This is why you should finish your tile pool step with the Laticrete SpectraLOCK grout. This waterproof grout requires three parts of which two are included with the kit pictured here. Be sure to also choose the SpectraLOCK part C in the color that you are looking for.
How To Prepare Your Pool Step For Tile
Before you go and buy yourself a few square feet of tile and a bunch of Laticrete products you need to know more about how to prepare your steps for tile. The biggest
concern that you have is that your new tile installation is only as good as the substrate that you are bonding to. If you have an older concrete pool, or a top step
that already shows signs of deterioration, then you will need to take a few steps backwards before you can take a step forwards.
You will need to remove any loose or compromised concrete on the step treads. Compromised concrete can be a little more tricky to spot if you don't know what you are looking for. Basically, as concrete ages it will become less and less water resistant. As water passes through the concrete it will cause the cement within the concrete to dissolve and travel with the water. This will leave only the aggregate component of the concrete behind. Without the cement "glue" to hold all the aggregates together, the strength of the concrete will be dramatically reduced. If the steps in your pool feel weak, and you can poke and scrape them with a screwdriver and remove small chunks of sandy concrete, then you need to remove some of this concrete before proceeding to install tile.
In some cases the concrete will be thoroughly compromised and you will need to chip (jackhammer) a few inches of concrete out of the top step. If this is the problem that you have, then you will need to pour new concrete where you have chipped away the compromised concrete before you can begin with the Laticrete membrane layer. If you need to pour new concrete on your steps then you can learn about how to bond new concrete to old concrete in this article on concrete working basics. You will need to attach a wood board to the face of the stairs to help you re-pour the top of the step that you had to remove. In most cases it will not be necessary to actually jackhammer out the top of the steps...in most cases you will be able to simply remove the top 1/4" of concrete.
In most cases the concrete of your top step will need some remediation, but not as far as actually jackhammering and pouring new concrete. In most cases the use of a diamond cup wheel on an angle grinder will provide a perfect (and level) surface to begin your membrane and tile setting.
A diamond cup wheel attached to an angle grinder is not something intended for novice hands. Angle grinders are a very dangerous, high RPM tool, and a diamond cup is heavy. It takes a strong, confident hand to use a diamond cup on a grinder. If you want to be able to have a little more control then you can consider picking up a variable speed grinder.
Use the diamond cup to grind down the horizontal surface on the top step and do your best to have the end results be as flat and level as possible. Usually you will not need to go more than 1/8" or 1/4" with the cup grinder before you expose substrate suitable for building off of. The diamond cup is not suitable for removing an inch or more of concrete from the step - if you need to remove that much concrete you should be using a chipping hammer and re-pouring the step with concrete before proceeding with tile.
Can Tiled Steps Also Fail?
Tiles, while much more resilient than mortar based interior surfaces, can still fail from improper installation (more inadequate installation) as well as harsh freeze
and thaw conditions. So long as your tiles are frost rated, and preferably porcelain, there is little chance the tiles themselves will crack. More likely that the
water will be able to get underneath the tiles and into the substrate which will almost certainly result in at least a few popping off. The water under the tiles can
freeze and cause a mechanical separation in the thin set, or mud base layer, but also the ice can "grab" the tiles if water is both underneath and overtop of the tile
itself. As the ice in the pool migrates even to the smallest degree, the tiles will have no choice but to pull off with the force of the moving ice.
This is why, especially in cold climates, you should protect your tile installations by having a waterproof membrane layer that will prevent water from getting under the tile as well as protecting the tile against shifting or cracking substrate conditions. For more information about why tiles fail, and how to set tile in swimming pools you can read this article on how to fix pool tiles.
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