Concrete sealers are used to keep concrete uncontaminated and safe from any sort of impurities. They are used because of the porous nature of concrete. This saves them from any sort of cracking and corrosion over a long period of time. Hence, concrete surfaces last longer, and they are ideal for driveways, pathways, and walkways.
However, there are times when you need to remove the concrete sealer. This could be because you want to apply a new, better sealer to the concrete for preservation. It could also be because you need to completely break apart a concrete pathway or walkway. Hence, stripping the concrete sealer makes the job easier.
Here is a guide on how to remove concrete sealers.
Removing Concrete Sealers with Chemical Strippers
There are two main methods through which you can remove chemical concrete sealer.
Mechanical Method
This method involves blasting, grinding, or sanding over the surface of a walkway or pathway. This is a destructive pathway that can lead to a lot of mess. It creates a lot of noise and generates a lot of dust. Sometimes, the damage is so complete that no more decorative finishes can be applied. Hence, if you’re not just breaking the surface to completely revamp it, don’t use this method.
Chemical Method
This process uses chemical solvents called strippers to remove the sealer. This method can allow for the concrete to be resealed with a better sealer. It also allows for further work to be done on the concrete without creating a mess. This method preserves the walkway or pathway on which the finishes can be applied.
Types of Chemical Strippers
There are three main types of chemical strippers that can be used to remove concrete sealers.
- Caustic
- Solvent-Based
- Biochemical
These chemical-based strippers can be bought at any concrete distribution house or big-box outlet. However, whichever category of chemical strippers you use, you can get great results. Remember that they contain a lot of harsh chemicals, so make sure to take safety precautions when using them.
The green and environmentally-friendly chemical-based cleaners aren’t safe to use without protection. They contain chemicals that aren’t safe for consumption or inhalation. They can make you sick, so you should take the proper precautions no matter what.
Caustic Strippers
These strippers consist of alkaline chemicals. They rank high on the pH scale and, hence, cause the destruction of the chemical coatings that line the concrete. The sealers break quite easily upon the application of strippers.
Use Case
Caustic strippers are the best option when you’re dealing with the type of concrete sealers that contain latex or alkyds. They also work great on enamel paints that are used over concrete. They aren’t great for removing acrylic, epoxy, or polyurethane. These coatings have a huge resistance when it comes to caustic chemicals.
Another thing to be wary of is that caustic chemicals aren’t very effective below 50 F. Thicker buildings also require a lot of layers and applications. While this may be true of a lot of chemical strippers, for the caustic ones, it’s especially true.
Safety Precautions
As discussed before, the harsh chemicals in strippers require the utmost precaution. You need to put on physical protection in order to avoid the harsh alkaline corrosion from a caustic stripper. Once the stripper has done its job, you need to apply a neutralizing wash. This will remove the coating from the concrete, and any residue from the stripper.
Make sure that you dispose of the waste material properly. Caustic strippers have a tendency to stay active after they’ve been applied and/or neutralized. They can react with a lot of chemicals after they’re removed from the concrete.
Solvent-Based Strippers
These chemicals are the most common types of strippers in use today for concrete sealer removal. They became popular because they work fast, and because they’re the most powerful. The most popular types of solvent-based strippers are based on methylene-chloride.
Other types include dibasic esters (DBEs) and N-methyl pyrrolidone (NMP). Also, there are other solvent-based chemical strippers that contain alcohol, toluene, and acetone.
The trick with these kinds of strippers is that they only work when they are wet. They need to be mixed with water and can’t work without it. Solvent=based strippers require constant application of water in order to be effective. If no steps are taken to reduce the evaporation of the strippers, then they won’t work as well.
Once the coating is done, the application of water and soap is needed. The surface needs to be rinsed with clean water after. Using a high-pressure washer is best for cleaning the surface.
Use Case
Since solvent-based strippers are very fast and very effective, they are very popular. Their use case is almost universal. They will work to remove concrete sealers of all types. Any acrylic, polyurethane, epoxy, polyaspartic or polyurea based sealers are no match.
However, you need to realize that these strippers are only good for cool conditions. If you use them on a hot day or in a climate that supports arid conditions, they will fail. Heat and wind will do you no favors with a solvent-based chemical stripper.
Safety Precautions
Solvent-based strippers can cause a lot of irritation in the skin. They can also cause a lot of liver damage upon excessive use. Some precautions include great ventilation and a good circulation of air. Also, wear latex and goggles during the application.
Biochemical Strippers
These are the newest category of stripper. They are very popular since they stem from sustainable materials. Their plant-based roots mean that they don’t harm the environment as much. They contain a lot of natural acids and esters found in plant sources.
Use Case
Environmentally sensitive areas call for such strippers to be used. If a garden walkway is being built, or botanical gardens are being restored, this is the stripper for the job. The biochemical stripper won’t kill grass or plant life; it will not erode or corrode any of the plant species around the concrete. They also have next to no odor.
The downside is that these strippers are the least effective. They require the most active application and require long periods of application to stick. They can take anywhere from 10 to 20 hours in order to remove an epoxy layer of concrete sealer.
Safety Precautions
A common ingredient in most biochemical strippers is N-methyl pyrrolidone (NMP). While this only causes minor skin irritation, physical protection is warranted during application.
Chemical strippers can be very useful in the removal of concrete sealers. They not only help you maintain the concrete for renewal but make short work of concrete sealer removal.
