Will a Pressure Washer Remove Sealer From Concrete? 

 August 29, 2021

By  Dale Keese

It's pretty much a guarantee that anyone who has ever stripped sealer from a concrete surface will find the experience frustrating. It is one of the most difficult tasks to remove old, worn, and failing sealers from concrete. This is unfortunately the only way to prepare, restore, or repair concrete surfaces.

A pressure washer can remove old concrete sealers. The sealer can be removed from concrete by using a pressure washer with a wand or an orbital walk-behind model. Keep in mind, however, that even though this method is effective, it may not completely remove the old sealer.

In addition, you may need to rent expensive equipment if you do not have access to a hot water pressure washer. Furthermore, with this method, water is reabsorbed into the concrete surface, which is not ideal if you plan to reseal right after.

How to Pressure Wash Water-based Sealer From Concrete

Before pressure washing sealer from concrete, you need to determine first whether it’s water or chemical-based. Water-based sealers can be easily removed by pressure washing, but chemical sealers can be tricky. When it comes to concrete sealers, becoming aware of whether they are water-based or chemical-based products is an important consideration, as water-based sealers cannot be applied over chemical-based products and chemical-based sealers cannot be applied over water-based materials. Use Xylene to treat a small area of concrete. Allow the Xylene to sit for 20 seconds, then touch the concrete. Sealants made of chemicals will gum up and become sticky, whereas products made of water won't.

Pressure Washing Water-Based Sealers

By using a pressure washer, you can remove water-based sealers. Water at high pressure can break the concrete coating off, washing away the debris.

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    Ensure that the concrete surface is clean and ready. With a cleaning cloth, wipe off dust, dirt, and debris from the concrete surface. Use a broom to sweep off the dirt and water to wash away the dust if the area is large.  Make sure the surface dries completely.
  2. 2
    It’s essential to prepare the surrounding area. It is important to keep in mind that high-pressure washers can damage wood, cut skin, and strip paint from surfaces, so eliminate any plants, furniture, or other objects nearby. Protect nearby fixtures and other sensitive surfaces with a waterproof cover if you can't. If you plan to use a chemical seal remover, you should also close all nearby windows and doors. This prevents potentially harmful fumes from entering your home.
  3. 3
    In order to soften the seal, abrade the concrete with seal remover. Choose one that is appropriate for the type of sealer used on the concrete surface. A concrete sealer remover that is water-based or solvent-based can be used to remove water-based sealers. Directly pour the remover solution onto the surface. As the chemicals can be hazardous to your health, put on gloves, a mask, goggles, and close-toed shoes before you begin this project. As directed on the label, let the solution sit.
  4. 4
    Using a pressure washer, remove the concrete sealer. Make sure you are using a pressure washer that has a 3000 PSI setting. Clean away the residue left by concrete sealer remover and the old sealer layer using an appropriate nozzle. To effectively blast away sealer chips from the surface, point the spray downward and move it in a sweeping motion. Keep 12 to 18 inches of separation from the concrete surface when holding the washer wand. Water will penetrate the coats of the sealer at this angle and distance without destroying the concrete surface. If it is a large area of concrete, you may want to divide it into more manageable portions.

Can Pressure Washing Destroy Concrete?

Pressure washing your driveway and sidewalks can be a rewarding, but time-consuming, task. It virtually eliminates built-up dirt, debris, and stains, but is pressure washing hazardous to concrete? The quick answer is yes, pressure washing can destroy concrete.

Even when using a light-duty power washer, the water pressure can cause visible damage. In this case, you can cause irreversible damage to your driveway or patio if you are not careful. Additionally, some types of concrete are weaker than others, making certain areas more susceptible to developing lines, pitting, or surface defects, on top of the deterioration of joints due to washing away of mortar or joint sand during the process.

There are several reasons why pressure washing can cause damage, including the use of the wrong nozzle, overuse of pressure, and spraying too close to concrete surfaces.

Does Power Washing Remove Concrete Sealer?

Power washers are versatile machines that can be used around the house to clean and restore a variety of surfaces. For those who do not want to invest in a power washer, they are readily available to rent at home improvement stores or most hardware stores. Without the proper knowledge, pressure washers can damage your surface. Make sure that you figure out first what type of concrete sealer you’re dealing with, before deciding to use a power washer.

Concrete sealer can be removed mechanically or chemically. In the mechanical method, the sealer is physically removed by grinding, sanding, or blasting. In removing sealer chemically, you have a variety of chemical strippers to choose from. Power washing can remove water-based sealants from concrete, but not solvent-based ones.

Sealing Concrete Driveway After Pressure Washing

Pressure washing and sealing your concrete driveway every few years will keep it looking good. Concrete sealers keep water from finding its way into the imperfections and pores that cause cracks and crumbles in the concrete. Furthermore, sealers prevent stains on concrete from setting in. The process of sealing concrete after pressure washing is as important as painting your home's walls.

Cleaning the Driveway With Pressure Washer

Based on how deep the stains are, choose the right spray tip for your pressure washer. The narrow-pattern spray tips can mark concrete but are intended for tough stains. The wide-pattern spray tips are low-pressure. Many models come with nozzles specifically designed for spraying cleaners. You can purchase universal spray tips and nozzles if yours does not include them. Also, make sure you wear safety gear.

Using a garden hose, wet the entire surface of the concrete. Apply soap with the spray tip or nozzle. Next, hook a hose to the pressure washer. Make sure to keep the water flowing steadily through the machine. Connect the siphon tube of the pressure washer to the concrete cleaner container. Turn on the pressure washer. Apply concrete cleaner thoroughly. Make overlapping strokes with the wand. Soak the cleaner for 3 or 5 minutes, but don't let it completely dry. To better control drying, wash the concrete in smaller sections.

Clear the siphon tube of the detergent before rinsing away the cleaner to avoid applying more soap. As a tip, you can put your siphon tube in a bucket of clean water. Then flush out your pressure water until the soap is cleared. Change the spray tip from a high-pressure to a low-pressure one. Make the same overlapping strokes with the wand. The wand should always be moving to prevent etching your concrete.

Sealing the Driveway

The driveway can be sealed after it has dried for at least 24 hours. A sealer protects your concrete from staining and damage. Some sealers have a shiny finish, while others are matte. When applying the sealer, wear splash-proof goggles and chemical-resistant gloves.

Apply the concrete sealer with a sprayer or roller. If you’re using a garden sprayer, put the sealer into the sprayer's tank. Using overlapping strokes, cover the concrete completely. Don't allow the sealer to accumulate. To remove buildup, use a rag to wipe it away. After completing the first coat, let it dry completely. If you're applying the sealer with a roller or brush, do so just as you would when painting a wall. For the edges and seams, you will need a large paintbrush. In case of rippling buildup, roll the brush over it to move the excess to the front. 

After applying the first coat evenly, let it dry completely. Keep in mind that you should never use a garden sprayer that’s been used for spraying pesticides.

Before painting the second coat, check the sealer instructions. The brand of the sealer you use may require you to apply the second coat at a different angle for better coverage. For best results, let the concrete sealer cure according to the directions.

Sealing Concrete Patio After Power Washing

A power washer is one of the most effective means of removing deeply embedded dirt from surfaces including hardscapes. Unfortunately, it can also lead to significant damage to concrete patios if it is not used correctly. After power washing your concrete patio, sealing it prevents water from penetrating the holes, which then freezes and causes cracks. It is especially important to seal a concrete patio in colder climates where hard freezes occur frequently. Furthermore, sealing prevents oil and grease stains.

Cleaning the Patio With Power Washer

To clean the concrete patio with a power washer, choose a wide-angle tip. Afterward, you will need to prepare the cleaning materials. Your choice depends on what you want to remove from your patio. Mold, grime, and algae can be removed with just water alone. In case of oil stains, however, you should consider adding a soap attachment.

Once you have selected your equipment or material, go ahead and get started. For best results, ensure you are using the proper techniques. You should begin by sweeping your patio uniformly beginning at one end. For reduced streaking, keep the tip about 12 inches from the surface of the patio. When the tip is held too close to the surface, it can damage the concrete. It is also recommended that you spray at a tilted angle to reduce the force the water jet exerts on the concrete, and minimize damaging your concrete patio.

After power washing, the whole area, clean off any loose dirt or debris. Consider a rotating sweeping attachment if you have a rather large patio that may prove difficult to wash manually. With its rotating head, large areas can be cleaned quickly and evenly.

Sealing the Patio

Let your patio completely dry before sealing it. Temperature affects how quickly sealers dry, so think about when to seal. Keep in mind that you don't want your sealer to dry up too fast after you apply it since that can leave behind visible unattractive lines. Consider working before midday when the temperature is lower to prevent such aesthetic mishap.

Stir the sealer well in the sealer bucket using a paint stick as a preparation step. After that, attach your normal paint roller with your medium-nap roller. In contrast to normal paint rollers, medium-nap rollers work sealers into even tiny crevices in concrete surfaces.

Now it's time to seal. Using a paint roller, load the sealer so that it's well saturated, and be sure not to overdo it. Next, apply the sealer in a zigzag pattern over the surface, ensuring that all parts are covered. Keep in mind to overlap the roller strokes since this will allow each subsequent coat to blend seamlessly with the previous coat. Make sure to let the first coat dry completely before applying a second one if necessary. For the second coat, read the sealer label instruction as a second coat might not be needed; or if it is, you may need to use a different stroke to apply the second coat.

About the author

Hey, I'm Dale Keese.. thanks for reading.. hopefully this article can save you some time and trouble with your sealing job. I'm also in the process of making some video walk-throughs for youtube so check back soon! thanks

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