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concrete pitting

Concrete Pitting, Flaking, and Staining

Before your concrete fully pits, flakes, and stains, there will be warning signs. Catch these red flags early and save the integrity of your concrete!

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When concrete is newly poured, it looks satisfyingly smooth. Unfortunately, it doesn’t stay like this forever, especially when the concrete is outdoors. Over time, concrete surfaces flake, stain, and crumble. Holes and jagged gaps appear on the concrete, ruin its aesthetic, and ruin its external structure. 

Concrete pitting, flaking, and staining make a home look old. Homeowners who wish to sell their house need to tackle deteriorated concrete since it can bring down the value of the house. It can also cause problems when a smooth surface is required, like when your kids want to skate in the driveway or when you want to put a workbench in the garage. 

As concrete pitting gets worse with time, it can become a safety hazard. Here’s everything you need to know to spot concrete deterioration. 

Detecting Concrete Pitting, Flaking, and Staining 

As tough as concrete may seem, it does deteriorate over time. The erosion of concrete starts out small, but as the years go by, the damage becomes more significant, resulting in uneven, rough flooring. As the structure wastes away, the concrete becomes weaker. This allows moisture to seep through and affect the soil foundation underneath. It also means the concrete is more likely to crack and break. 

Before your concrete floor becomes a tripping hazard, you can learn to detect pitting and flaking. Observing how the concrete’s surface is reacting to exposure will help you understand how your concrete is changing. Here are the problem signs you can immediately detect so you can determine when it’s time to repair the concrete.  

  • Concrete Pitting Problem Signs 

Concrete pitting is when the surface of the concrete begins to erode. Pitting can be visually identified by the small, jagged craters that appear on the concrete. The craters either show up in clusters or individually. When there’s a cluster of holes in the concrete, it looks like a thin layer of concrete was scraped and torn off. The individual holes look more like someone grabbed a hammer and chisel and made the individual craters. 

Pitting is caused by problems with the way the concrete was mixed or poured. This means that there are problems with its internal structure and its strength. You can test the structural integrity of the concrete by lightly tapping it with a hammer. If the hammer bounces off the concrete, it’s still strong and most likely won’t deteriorate very fast. However, if the hammer forms another crater, it means the concrete is unsound and is bound to deteriorate quickly. 

When concrete begins pitting, it’s not very noticeable. Pitting is a rather slow process that begins when the concrete is being mixed. If the contractor did not notice any problems during mixing or while pouring, then the problems aren’t going to show up until a few years later. 

Another sign to watch out for is inconsistent concrete texture. When the concrete is poured, workers smooth it all out with various tools. As the concrete’s top layer gets worn down, the unpaved concrete gets exposed. You can instantly tell that concrete is extremely pitted when one part of it is smooth while bits and pieces of it are rough.  

  • Concrete Flaking Problem Signs 

Concrete flaking (also known as concrete spalling) is very similar to pitting, and it’s easy to confuse the two concepts. Concrete flaking only affects the very surface of the concrete, while the damage caused by pitting tends to go deeper. 

Like pitting, concrete flaking is a process that takes many years, so you won’t notice until the flaking has been going on for a long time. However, you might begin to notice after a particularly long winter. Concrete flaking is caused by freeze-thaw, so longtime exposure to water that keeps freezing and melting will have a big impact. Take a picture of your outdoor concrete before the first snowfall in winter and then compare it to what it looks like in the spring. 

The freeze-thaw effect greatly weakens the concrete, but what ends up flaking it faster is human tampering. When shoveling snow on the driveway, the impact of the shovel hitting the concrete greatly affects how quickly the surface flakes. Winter is definitely the time when concrete surfaces change the most. 

Besides observing your concrete to see flaking, you can also determine its flakiness using a tool. Grab a screwdriver, wrench, chisel, or any other tool with a relatively thin edge. Then, drag the tool across the concrete. If a white line appears, the concrete is structurally sound, but if it flakes off, you’ve got a problem on your hands. 

  • Concrete Staining Problem Signs 

There are many different stains and color changes concrete can go through. They are very undesirable because they make the concrete look dirty and old. Among the most popular type of stains concrete experiences include: 

  • Oil stains 
  • Blotchy discoloration 
  • Rust stains 
  • Efflorescence staining 

The oil stains are easy to spot because they are located where you would usually park or drive your car. They are dark in color and don’t wash away easily. Concrete is porous, so the oil stain isn’t just a puddle that settled on the surface of the concrete. It permeates through the concrete, which is why these kinds of stains are so difficult to get rid of. 

Discoloration can appear in concrete as blotchy dark spots. It looks as if it had rained and the concrete was beginning to dry. The difference between wet spots and discoloration stains is that the former is gone once all the moisture evaporates while the latter remains. These discolored spots aren’t caused by any liquids being poured on the concrete, rather by the materials used when mixing the cement. It’s an inherent problem with the concrete’s soundness. 

Rust stains are also easy to spot because they look like the concrete is rusting. This may not be a puzzling sight on concrete walls, which have rebar in them, but it may be confusing to see concrete pavements rusting. This is another stain that homeowners can’t get rid of easily because it was caused by a chemical reaction. Rust stains on concrete can only be removed with the use of harsh chemicals, so it is not advised that you try to remove the stains yourself. 

Efflorescence stains are white in color and look like someone spray-painted the concrete. However, this stain isn’t completely flat; the texture can often be very rough, and you can feel the difference between the efflorescent stain and the rest of the concrete. It’s raised and almost mossy looking, so it not only makes the concrete look bad, it roughens it out too. 

Can I Fix Concrete Pitting, Flaking, and Staining Myself? 

Pitting, flaking, and staining might seem like minor issues you could fix yourself, but repairing concrete is a lot more difficult than one would think. There are many resources online as well as products you can buy from a store that you can use to repair concrete. The problem with these DIY solutions is that they are very generalized and aren’t made with specific circumstances in mind. Applying general solutions to specific problems doesn’t fix the problem at all. As a matter of fact, it could end up making things worse. 

To make sure a job is well done, there’s a certain level of knowledge you must have for the tools and materials at hand; otherwise, whatever repair work you do will come undone in a very short time. For example, many DIY resources suggest using a cement patch to fix pitting and flaking. However, this won’t fix the issue in the long run, because the new cement does not adhere well to the old concrete, so the small patches will come right off and you’ll be back to where you started.  

  • Why DIYs Are a Big Problem 

One of the biggest reasons concrete deteriorates is because of its permeability. Whatever material you choose to pave the concrete will have to be less permeable than the concrete you currently have. If it’s not, the pitting and flaking will only get worse. If you try to mix the cement yourself to make sure its psi levels are ideal, you still run the risk of mixing the cement incorrectly and ruining the mixture. 

Many DIY products still require you to add water to the solutions. You would have to know just how much water you need to use to get the proper consistency. Remember, not adding the right water measurements is usually why concrete stains and erodes in the first place. 

You run into even more trouble if you wish to repair a very large area. Concrete doesn’t flake and deteriorate evenly. There can be spots on the pavement that are firmer and more difficult to chip away at than others, which is something you have to do when repairing concrete. If you don’t have the skill to chip away at the concrete like you’re supposed to, you run the risk of cracking and even breaking it. 

Getting rid of stains on concrete is even more difficult than fixing pitting and flaking. This is because you need special chemicals that can help you do the job. The problem with using chemicals is that they can be extremely harmful to you and your family’s health if you don’t use them properly. The chemicals can seep through the concrete or soil and leave an uncomfortable smell that doesn’t go away. 

Another common DIY suggestion is pressure washing, but there can be problems with this as well. If the concrete is already in poor condition due to pitting and flaking, the water pressure will destroy the concrete’s surface. Leaving the concrete exposed in this way can end up costing you a lot more down the line. Exposed concrete cracks more often, and those cracks make it easier for moisture to seep through. Moisture that reaches the soil underneath the concrete causes swell-shrink, which then leads to soil shrinkage and settling. 

Concrete Pitting, Flaking, & Staining


Many homeowners aren’t sure why their concrete suddenly has craters or why it’s flaking off, especially if the concrete was placed in a part of the house that isn’t used much. This has to do with the idea that concrete is an unmovable, difficult-to-break material that only cracks under extreme pressure. However, concrete experiences breakage even when left on its own after a few decades. 

The material isn’t as tough as it may seem. A big part of concrete’s vulnerability begins from the time the concrete mixture is made.  

  • The Freeze-Thaw Effect 

Flaking is caused by the freeze-thaw effect, in which water that seeps through the concrete freezes and expands. When water freezes and changes its state from liquid to solid, it expands by about 9 percent and puts pressure on the concrete’s surface. If the pressure exceeds the concrete’s tensile limit, the concrete particles get displaced. 

This occurs because of how porous concrete is. The water under the very surface of the concrete gets frozen and lifts the concrete up. Now detached, the concrete layer is able to flake off at the slightest touch. During winter, the freeze-thaw cycle is in full effect. Driveways in particular are vulnerable to flaking during the winter because of the shovels flaking off the already vulnerable concrete. This is why it’s important that contractors make high-strength concrete in places where it snows since stronger concrete is less permeable. 

  • Concrete Mixture  

The way the concrete is mixed has a huge impact on its color, stability, and strength. All concrete deteriorates over time, but if the concrete is pitting and flaking less than five years after it was poured, it was caused by an inadequate mixture. Contractors should make their mixtures based on the area’s climate. 

Low-strength concrete is more permeable. It would be all right to make low-strength concrete in a state like California, where it doesn’t rain or snow heavily. Low-strength concrete shouldn’t be used in a state like North Carolina, where it gets cold enough that the concrete goes through the freeze-thaw cycle.

Stains are ugly and undesirable. They make the concrete look old and dirty, and thus make the room or house look the same way. There are many reasons as to why concrete would stain, but let’s focus on the less obvious ones. Why concrete would have oil stains is a pretty obvious answer, but sometimes, even well-preserved concrete will stain out of nowhere. Here are some of the reasons why this would happen. 

  • How the Concrete Was Mixed  

How the concrete was mixed plays a huge impact on how it looks over the years. One of the biggest reasons concrete stains is the addition of calcium chloride. Calcium chloride accelerates cement hydration and reduces setting time by over 50 percent. However, the downside to using calcium chloride is that it stains the concrete because of its chlorine content. 

Too much water in the concrete mixture also causes stains in many ways. If there’s too much water, the sealant and the water never bond together, eventually resulting in the sealing agent evaporating faster than the water. Too much water can make the resin in a sealant bubble up, causing the concrete to stain while developing a frothy texture.  

  • Rust Stains 

Rust stains can be caused by two things: fertilizer and soil. Fertilizers contain minerals that have a chemical reaction when exposed to water. It’s very common for concrete near plants to have rust stains due to oxidative fertilizers. The mineral content in these fertilizers can also be transported via the homeowner’s shoe inside the house, where they will stain indoor concrete such as garage floors. Cars also bring in harsh salts and metals on the tire, where the concrete stains once it gets wet. 

North Carolina’s state soil is known as Cecil soil. It has a brown loam topsoil, but the rest of it is red clay soil. Red soils are rich in metals such as iron, which oxidize and give the soil its iconic red color. Unfortunately, the soil isn’t the only thing that turns rust red. The concrete slabs supported by the soil are also stained. 

Unfortunately, you can’t keep concrete in pristine condition forever. It will eventually deteriorate after more than five years. Sometimes, concrete pitting, flaking, and staining occurs to no fault on the homeowner’s part. If there are problems with the concrete mixture or the mixture was poured incorrectly, the concrete’s stability will fail no matter how many preservation tactics are put into place. 

There are prevention measures that can be taken to preserve your concrete for as long as you can. It’s not impossible to keep your concrete looking brand new, so take the following into account: 

  • Pitting and Flaking  

Most homeowners have no say in how the contractor mixes the concrete, especially if the house was bought and you weren’t there for its construction. However, if you do find yourself in a position where you can oversee cement pouring, try to talk to the contractor or site master about the usage of calcium chloride, as well as the mixture’s psi levels that determine the concrete’s strength. 

Pitting and flaking can be caused by freeze-thaw, so it would make sense to cover your driveway so it doesn’t get exposed to snow. You’ll also want to make sure your shoes are dry before stepping on any concrete. This might seem a bit inconvenient, but if you at least commit to only doing it during the winter, it will greatly help you preserve your concrete

  • Staining  

Again, if you’re in the position to talk to a contractor while overseeing a project, talk to them about the use of too many different materials used in the mixture as well since this can cause staining. Ultimately, every contractor will have their own way of mixing they might not want to change, so make sure you choose a reputable company to do your concrete flooring. 

Moisture will bring up salts and minerals in the concrete, so keeping the pavement covered is a good idea. Moisture doesn’t affect concrete as much as freeze-thaw does, but the risks of staining are still there when the concrete gets wet. 

Who Should I Call to Help with Concrete Pitting, Flaking & Staining? 

It’s definitely a lot safer to call an expert that can help you with concrete pitting, flaking, and stains. Not only will you be able to guarantee a full repair, but you will also guarantee that no further harm will come to the concrete. Professionals not only have the right tools for the job, they also have the right knowledge. 

Understanding how concrete behaves when interacting with moisture, chemicals, epoxy solutions, and salts is what allows contractors to do a good job when repairing concrete. Not only do they tackle the issue at hand, but they also make sure your concrete looks untampered with. 

When choosing a contractor to help with home repairs, you should always choose one with a good track record. Professionals who have not only been in the industry for years but are also locals familiar with the area’s climate, weather patterns, and soil. 

Tar Heel Basement Systems Can Help You with Concrete Problems 

Since 2003, Tar Heel Basement Systems has been providing accessible and affordable solutions for concrete repair for the homeowners of Raleigh and Winston-Salem, NC. We are an A+ rated, accredited member of the Better Business Bureau, and our track record is impeccable. Contact us today to schedule your free inspection and repair quote

You can trust the experts at Tar Heel Basement Systems to always be there to help. So don’t hesitate to call us if your concrete is stained or if it’s deteriorating. We’ll be more than happy to make your home look perfect once more.

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