Common Problems with New Pool Plaster

Written by Michael Dean
July 5, 2023

troweling new pool plaster

Whether you’ve just invested in a pool or thinking of doing so, understanding the basics of the pool plaster process is very much to your advantage. In addition, you should educate yourself on common issues that may arise with your new pool. This way, you will be aware enough to prevent a possible problem from occurring or fix it before it worsens. Several issues can arise with new pool plaster; as a pool owner, you must know how to identify and fix them.

In this article, I will discuss the common problems with new pool plaster and how to fix them.

Main Takeaways

  • A few common issues with pool plaster are spalling, crazing, mottling, discoloration, and algae bloom.
  • Most issues with new pool plaster can be prevented beforehand using a good plaster mix and healthy trowelling practices.
  • Acid washing or underwater plastering are solutions for dealing with superficial problems afflicting your plaster without replastering the entire pool.
  • Pool plaster takes approximately 14-28 days to cure enough for general usage.

Common Problems with New Pool Plaster

Here are some of the most common issues to arise with new pool plaster and classic signs of bad plaster jobs.


Spalling happens when the top layer of concrete has peeled away from the walls, also described as chipping or flaking. It appears as rough, irregular patching on the plaster walls and a slightly different shade than the surrounding area.

pool plaster chipping off

It can occur due to improper troweling, which depends heavily on time, weather, and temperature conditions. An inexperienced crew can also trowel improperly by adding too much water to the plaster mix or troweling too much or too little.


When small clusters of cracks in the shape of spiderwebs appear on the pool plaster, you’re looking at an issue called crazing. The cracks are very fine and shallow. Crazing is not a serious issue that is mostly surface-level. But while not excessively dangerous, it should not ideally show up in your new plaster since it’s a sign of poor plaster mix or excessive drying of the pool plaster.

Crazing occurs very early on in the stage of plastering and can be hard to spot until the pool is filled.


A speckling of color or a varying pattern of discoloration in pool plaster is known as mottling. It is easily identifiable and can be either light or dark, depending on the color of your pool’s plaster and makeup. It is a common issue caused by various factors, such as incorrect trowelling, uneven application, or improper water chemical balance.

pool plaster mottling

Ranging from mild to severe, mottling is primarily a harmless aesthetic issue that does not impact the lifespan of your pool or pool plaster.

Plaster Streaking

Pool plaster streaking happens your plaster develops uneven or discolored streaks. Streaks appear as lines or patches that don’t blend seamlessly with the rest of the pool. This can be caused by different factors, such as inconsistencies in mixing the plaster, improper application techniques, bad quality pool plaster, and issues with water chemistry during the curing process. The most effective way to prevent pool plaster streaking is to ensure that you are correctly mixing and applying the plaster.

Plaster Etching

Pool plaster etching is not a super common issue to occur with new plaster, but it can happen if your water chemistry is out of whack. When your pH or alkalinity is low in your pool, the acidic conditions can slowly corrode the plaster, eating away at the material. This is an issue that generally occurs over a longer period, but if you fail to keep your chemical levels in check, it can happen much quicker. Prevent etching by consistently testing your pH and alkalinity levels and balancing them when necessary.


Algae in the pool is a common problem nobody wants to deal with. Algae can grow in your pool due to poor water filtering practices and water chemistry imbalance. Spores can be carried into the water by the wind, a person’s skin, or the local climate. When your plaster is newly installed, algae can grow in your pool if you are not brushing the pool’s walls often enough – especially in the first two weeks.  You should also acid wash your pool before the new plaster is applied to avoid algae buildup.

Although algae is not generally unsafe, no one wants to swim in unsightly, slimy, green water! But with that said, some types of algae, such as black algae, can be dangerous.

How To Fix Common New Pool Plaster Issues

Now that we’ve identified the issues, how do we fix them if they occur? There are four main fixes to the above-named issues: acid washing, underwater plaster, paint, and replastering.

Acid Washing

Acid washing involves draining your pool and using a diluted solution of muriatic acid to dissolve algae spores, calcium buildup, iron buildup, mottling, and other common superficial plaster issues. It dissolves most buildups, releasing the trapped dirt underneath and revealing the true color of the plaster beneath.

To acid wash, drain the pool, and use a brush to apply a muriatic acid solution to your pool plaster and scrub! If you’re dealing with stubborn stains or discoloration, you could apply several light coats of acid. Do not, under any circumstances, use undiluted acid, and use the proper safety equipment if applying the acid yourself.

Underwater Plaster

If you wish to deal with a superficial defect in the plaster and do not wish to drain the pool or acid wash it (which can weaken the pool if done too often), a great alternative is underwater plaster or epoxy putty. To do this, you will need to chip away the problem area, create the plaster or epoxy mix according to the manufacturer’s instructions, and apply the putty underwater to the crack or defect with a trowel putty knife. Spread the mixture flatly and equally against the plaster’s surface.


When considering repair or improvement of the plaster, a step you can consider before opting for the hassle of replastering is a paint job. If the problem in your pool’s plaster is primarily superficial, such as speckling or crazing, it could benefit from an epoxy-based paint job. But this will work only if your surface is as yet unfinished or made up of a similar epoxy. If not, you could instead carry out an acrylic-based paint job, which does not last as long as an epoxy coat but is easier to mix and apply. Both are great options to fix any shallow, superficial issues that need covering up.


If the pool plaster issues you’re dealing with affect a large area of your pool, or you’re dealing with a more severe problem, such as delamination, you may need to consider replastering the whole pool. I know this can be a huge pain, especially if you have only just recently plastered. But, if something went wrong during the process and the plaster is not applied correctly, replastering may be necessary. Replastering involves completely removing the plaster on your pool and replacing it with a fresh mix.

Generally, pool owners have to carry out a replastering job every 10-20 years, but it may be necessary before this time. However, since replastering is a significant expense, with costs around $7,000 for a 1000-square-foot surface, it is advisable to consult a professional before taking this step.

Do’s and Don’t’s For Properly Curing New Plaster 

Properly curing new plaster is half of the work in ensuring your new pool plaster looks great for the remainder of its lifespan. Here are some of my do’s and don’t’s when it comes to curing new plaster. 

  • DO fill the water continuously when filling your pool for the first timee; this is vital to ensure the plaster does not stain.
  • DO brush your pool twice daily for the first two weeks of the start-up procedure to aid the curing process.
  • DO use a nylon brush, which is gentle, and brush your pool walls carefully from top to bottom and from the shallow ends to the deep towards the drainage.
  • DO run your filtration system for 72 hours without stopping and once the water is clean, begin balancing it immediately according to recommended guidelines.
  • DO also clean your pool manually for debris, in addition to running the filtration system, using a pool net to fish out any debris. Shield your pool with a cover when not in use to protect the water from the elements and litter.
  • DO NOT pour any chemicals into the pool directly when balancing. Instead, dilute your chemicals for mixing in a five-gallon bucket first. It is best to consult a professional expert for the initial stages of treating the water, especially if you’re new to being a pool owner.
  • DO NOT shock your pool during the first month of usage.
  • Do NOT use the following devices until the start-up procedure is completed (which is approximately 28 days): automatic cleaners, pool heaters, and saltwater generators. Doing so could cause them to either get clogged with the plaster dust or damage the plaster.
  • Do NOT let the pool plaster be exposed for too long.

Check out my article on common swimming pool plaster issues for more issues that may not occur with new plaster.

Frequently Asked Questions

How long does it take for pool plaster to cure?

Pool plaster takes around 28 days to cure enough for the pool to be used for swimming, heating, or automated cleaning. However, the entire process can take much longer, up to 10 months, to cure completely. Make sure to wait the appropriate amount of time before filling the swimming pool.

How can I avoid staining my new pool plaster?

While some problems are unavoidable and occur due to factors beyond your control, you can avoid staining by following some simple steps, such as maintaining the chemical balance of the pool water, brushing regularly (even after the curing process is over), and acid washing. You can also add algaecide to the water to prevent algae buildup and sequestering agents to prevent metals in the water from staining the plaster.

More questions? Let me know. Also, be sure to check out my guide on the new pool start up process for more tips on tasks you need to complete after construction.

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