What To Do If Your Pool Plaster Is Chipping Off

Written by Michael Dean
July 5, 2023

pool plaster chipping off

Plastering your pool can make your pool that much more aesthetically pleasing while also protecting the pool structure. But some pool owners face a common issue: pool plaster peeling and chipping off. This not only looks unsightly, but it is also damaging to the pool plaster in the long run.

If your pool plaster is chipping, this article will provide you with different fixes and explain why your plaster is chipping in the first place. I will also give some valuable tips for how to prevent this problem from happening and explain what other pool plaster problems you may encounter.

Main Takeaways 

  • Pool plaster chipping off is caused by poor plaster application techniques, specifically trowelling.
  • Some fixes include: using underwater pool plaster or epoxy putty or replastering the entire pool.
  • Prevent pool plaster from chipping off by filling the pool water quickly after plastering, not troweling too much or too little, and avoiding plastering the pool on excessively hot/dry days.
  • Other pool plaster problems you may encounter are mottling, delamination, etching, and streaks. 

Why Is Your Pool Plaster Chipping Off?

You may notice that the plaster on the pool walls is chipping and flaking off. This pool plaster issue is called spalling.

Spalling most commonly occurs on areas like the steps, the shallow end, the sides of the wall, and near the main drain. Spalling can happen immediately after plastering your pool or years later.

Here’s an example of what it looks like on a swimming pool I had to replace a few years ago.

pool plaster chipping off

It is important to note that pool plaster chipping or flaking is not actually caused by poor water pH levels, but unbalanced water does not help the problem either. Low pH and calcium levels can wreak havoc within your pool water and plaster. There are several reasons why spalling could happen in your pool.

Improper Plastering Techniques

One of the most common reasons this problem occurs is improper plastering techniques during the plastering process – specifically, the troweling process. When the plaster is applied to the pool walls, you must trowel the plaster after it has dried a little bit.

Troweling plaster that still has water on the surface will force the water back into the plaster, which causes the plaster to weaken when cured. Weak plaster is more likely to start chipping away.

Plaster Dried Too Fast

The second reason your pool plaster may be chipping off is that during the plastering process, your plaster dried too fast. Pool plaster cures underwater, so I recommend filling the pool as soon as the plastering has been completed. If the plaster dries too fast on the surface, a dry crust will form on the outside while the inside remains wet. This weakens the plaster.

Plaster drying too fast is caused by the following:

  • Plastering on dry, hot days
  • Plastering on days with low humidity levels
  • Too much time between troweling
  • Late troweling
  • Too much troweling

Surface Impacts

Some other spalling causes could be surface impacts like suction cleaners or heavy-duty vacuums. But if your pool plaster is appropriately applied and cured, your heavy-duty cleaner really shouldn’t be causing your pool plaster to chip off.

What To Do If Your Pool Plaster Is Chipping Off 

If your pool plaster is chipping off, there are several ways to fix the problem.

Before you fix the chipping plaster, you will first need to sand down the entire area where the plaster has started chipping. You can use both wet and dry sandpaper to do this. Once that’s done, you can use one of the below fixes.

Replaster The Patch

A popular way of fixing chipped pool plaster is to use underwater pool plaster and replaster the entire patch that is chipping. The best thing about these underwater plaster products is that you do not need to drain the pool to do this. When applying, ensure the patch is completely smooth, and use a trowel to apply it as evenly as possible.

Epoxy Putty

If the chipping in your pool is in a small enough area, your other option is to use an epoxy putty and fill in the areas where the plaster has chipped away. Make sure you apply the putty around the outer edges of the area where the chipping occurs. This should help slow down the rate at which the chipping spreads.

Once you have pressed the putty into the chipped areas, use a trowel to smooth down the patches and apply an even layer of epoxy in the area.

Replaster The Entire Pool

If your pool plaster is chipping in a large area and around the entire pool, it may be time to replaster the entire pool. Although it is a huge and costly process, it will save you both time and money in the long run.

How To Prevent Pool Plaster From Chipping Off

The only way to prevent your pool plaster from chipping off is to ensure that the plaster is applied correctly in the first place. This can be done by not letting the pool plaster dry too quickly, filling the pool too slowly, waiting too long to begin troweling, troweling too little, and troweling too much. Ideally, you should hire a professional to plaster the pool for you to avoid this costly pitfall.

You can also prevent your pool plaster from chipping even further by ensuring that your water chemistry is always balanced. Regularly testing the pH levels of the pool water and using the correct amount of chlorine will go a long way in preventing any further chipping in the pool plaster.

Other Common Pool Plaster Issues

On top of chipping pool plaster, there are several other pool plaster issues that pool owners face. These include mottling, delamination, etching, and streaks.

Mottling is the discoloration of pool plaster that can occur due to a high amount of calcium chloride, incorrect construction, and unbalanced water chemistry. Though blow-torching and acid washing are two potential fixes for this problem, the only real fix is replastering the entire pool. Thankfully, since mottling is only a superficial issue, the stains won’t affect the integrity of the pool itself.

Delamination is a problem that causes pool plaster to lift and peel off the concrete underneath. This happens when air gets between the layers of pool plaster and the concrete base. This problem can happen naturally over time, but poor plastering techniques also cause this problem. You can use epoxy putty to fix this issue if it’s in a small area, but the only fix for severe delamination is to replaster the whole pool.

Have you ever gotten out of a pool and wondered why your feet are sore and red? This is because of etching. This problem causes the pool plaster surface to become excessively rough on the swimmer’s feet and results in lines, scratches, and dents that leave indentations in the pool plaster. This issue is caused by unbalanced chemicals in the pool water and can be fixed by sanding, replastering the section, or resurfacing the whole pool.

Another problem you may encounter in your pool is streaking. This is also known as discoloration of the pool plaster in the form of white streaks. This problem can be caused by troweling the plaster too late and disturbing the surface aggregate. Streaks in your pool plaster can also be caused by trowelling while there is still water on the surface of the new plaster. An acid wash may be of help here. The only way to prevent streaking is by proper plastering techniques.

Questions? Let me know.

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