While the only requirement is porosity, we typically recommend cleaning the concrete before sealing to avoid trapping any stains or making them harder to clean later. If pressure washing is possible, it is the best way to clean your concrete without the risk of discoloring the surface with a chemical cleaner.
Instead of penetrating past the surface, these sealers bond to the surface of the concrete substrate. However, if the concrete is dirty and has not been cleaned, then the concrete sealer will not bond to the surface of the concrete.
This is true of both penetrating and topical sealers. Penetrating sealers usually fully dry for traffic in less than 24 hours with topical sealers generally taking up to 48 hours to fully dry for traffic.
New concrete must be etched before applying the topcoat. The smooth surface of un-etched concrete won't bind as strongly with sealants, and as a result, you'll see your new sealant peeling and lifting away as it fails to adhere to the surface.
Sweep off or vacuum up any loose dirt, dust, and debris from the concrete surface. Using a garden hose, wet the concrete. Then, apply a mixture of trisodium phosphate and water, scrubbing the solution onto the surface using a stiff-bristled broom. You can also use a pressure washer for this step.
Even though it is easy to care for, the unsealed concrete used for garage floors, sidewalks, and patios will look better with a good cleaning. You'll need a stiff-bristled broom or shop vac, rubber gloves, trisodium phosphate, and any necessary stain removers.
Oil leaks, blood, and sticky residues can absorb and result in stubborn stains. However, using a driveway sealant after pressure washing can help prevent these stains from becoming permanent features in your driveway.
Concrete sealers are best applied in two thin coats. The first coat of sealer acts like a primer. Most of it will disappear into the concrete surface, and the concrete will probably look fairly unattractive after the first coat. The second thin coat will provide an even finish, color enhancement and gloss.
A strong enough power washer will blast most types of sealer off of concrete with ease. The trick is to make sure to pressure wash the entire surface area. For more sturdy sealers, it may take a few passes with the pressure washer to get it completely removed.
Sealcoating a driveway without thoroughly cleaning it first would be like painting a dirty wall on your house. It might look fine on the surface, but underneath, bad things are happening. Applying a coating on top of agents that are harmful to your driveway means they are sealed in and continue doing their damage.
A pH-neutral cleaner is always a good option for a final cleanse or to routinely mop with. No matter what is used to clean, it's crucial to allow the unsealed concrete to fully dry.
Yes, vinegar is an excellent concrete cleaner. This solution can strip surface-level messes from concrete. Due to its acidic properties, vinegar can be a powerful tool for breaking down offensive materials such as dirt, stains, and bacteria.
Alkaline cleaners are great for lifting oil stains, grease stains, and other petroleum-based stains from concrete. It's an added benefit that you can use it with a pressure washer, making the job that much easier. For an eco-friendly cleaner, we recommend Oil Eater cleaner degreaser (US$15.74, Amazon).
Use a mild grease-cutting detergent such as Dawn or Ajax dishwashing liquid mixed with water and a natural or synthetic bristle scrub brush to help brighten the patio surface. NOTE: Never use a wire brush as it can leave rust stains and scratch the concrete surface.
Natural Stone Countertops. Granite, marble and concrete are porous. Spraying these surfaces with vinegar can cause etching and loss of shine.
Phosphoric Acid – Phosphoric acid is a milder and less dangerous etching agent than hydrochloric or muriatic acids. It's great for lighter, decorative applications because it won't damage the surface of the concrete, but it won't be effective in breaking down tough materials like grout.
Don't acid etch the concrete if the temps are below 50 degrees as the acid will not be as effective with the cooler temperatures. Also, make sure your floor has dried thoroughly before applying a concrete sealer. Fans will help. Give it at least two days with warm weather and longer if it's humid or cooler.
Cleaning concrete with muriatic acid can be a highly effective solution if used correctly, providing ultra-bright white concrete and removal of many types of stains. In one application, you can remove rust stains, oil stains, algae, and paint splatter with a quick chemical application followed by pressure washing.
The Drawbacks of Seal Coating
One is that it can be messy and difficult to apply evenly. It's also important to note that sealants will not repair significant damage to your driveway; they will only protect it from further damage. If your driveway is damaged, you'll need to have it repaired before sealcoating it.
You can apply sealer at any time of day as long as the pavement temperature does not fall past 40 degrees at night. You can even apply the sealcoat during the nighttime. Many people choose to start their sealcoat project around 10 AM as the sun's temperatures begin to rise, and the humidity is not too oppressive.
The best temperature range for applying sealcoat is between 55 and 90 degrees Fahrenheit. Ideal temperatures are those that start around 70 degrees Fahrenheit in the morning and increase throughout the afternoon.