Resealing Concrete Patios: A Diy Guide To Success

Sealing a concrete patio is a great way to protect it from stains, foot traffic, and UV rays, which can cause the concrete to fade and discolour. It also makes the patio easier to clean and improves its overall appearance. However, resealing concrete is not as simple as it seems. To achieve the best results, it is important to follow a few key steps. Firstly, the concrete surface must be cleaned and prepared by removing any dirt, grease, or existing coatings. Then, if there is any old sealant, it needs to be stripped away. After that, a new sealant can be applied, but it is crucial to allow sufficient drying time between coats and before using the patio again.

Clean the surface

Cleaning the surface of your concrete patio is a critical step in the resealing process. An improperly prepped surface can lead to issues later on, such as poor adhesion and uneven coverage. Here is a step-by-step guide to cleaning your concrete patio surface:

Step 1: Remove Debris and Surface Contaminants

Start by clearing away any furniture, potted plants, or other items from the patio. Then, use a garden hose or a pressure washer to rinse away dirt, debris, and surface contaminants. If using a pressure washer, be careful not to set the pressure too high or hold the nozzle too close to the concrete, as this can damage the surface. A power washer with a PSI rating of 3000 or higher is ideal for effectively cleaning concrete.

Step 2: Apply a Cleaning Solution

If your patio is especially dirty or stained, you may need to use a cleaning solution. For light cleaning, a small amount of liquid dish soap applied with a push broom or nylon brush will suffice. Scrub the surface gently and then rinse thoroughly with a garden hose.

For heavier-duty cleaning or to remove grease, paints, waxes, and other stubborn contaminants, use a neutral cleaner specifically designed for concrete. Products such as MasonrySaver Cleaner & Degreaser or MasonrySaver Safer Brick & Masonry Cleaner can effectively clean and prepare the concrete surface for resealing. Always follow the manufacturer's directions for cleaning and safety.

Step 3: Rinse and Dry the Surface

After cleaning, thoroughly rinse the patio with a garden hose or, if using a pressure washer, use the round surface attachment to avoid damage. Ensure that all soap or cleaning residue is removed. Once cleaned, allow the surface to air dry for at least 24 hours. A leaf blower can be used to speed up the drying process.

Step 4: Inspect for Damage

Before resealing, it is important to check the concrete surface for any cracks or other signs of damage. Address any necessary repairs to ensure the new sealer adheres properly and to prevent further damage.

By following these steps, you will ensure that your concrete patio surface is immaculately clean and prepared for the resealing process, resulting in a smooth and uniform finish.

Remove old sealant

To remove old sealant from a concrete patio, start by testing whether your concrete has been sealed. You can do this by pouring a cup of water onto the concrete. If the water beads up and stays on the surface, it's sealed. If it soaks into the concrete quickly, it hasn't been sealed.

There are several methods for removing old sealant, but caution should be exercised as incorrect methods can damage the concrete. Sandblasting is an option, but it is not recommended unless you are experienced with using the equipment. The most effective way to remove old sealant is to use a chemical stripper. Chemical strippers are acid-based and caution should be used when applying them. Make sure to wear protective clothing, gloves, and eyewear as specified by the manufacturer. There are also less toxic and environmentally friendly products made from soy or citrus that will break down the existing sealer, but these take longer to work.

Once you have chosen your chemical stripper, use an airless paint sprayer or a 1-inch nap roller to spread a thick coat of the stripper onto the concrete. Follow the manufacturer's instructions to determine how long to leave it on. You should then see bubbles or crinkled areas that have formed on the surface. Use a long-handled scraper to remove the sludge and discard it. Contact your local waste center for the correct disposal method.

After removing the sludge, scrub the floor with trisodium phosphate (TSP) and water. Then, collect the remaining water with a shop vacuum. Let the concrete dry for at least 24 hours before applying a new concrete floor sealer.

Fill cracks and smooth the surface

Filling cracks and creating a smooth surface is an important step in preparing your concrete patio for resealing. After you have thoroughly cleaned the surface of your concrete patio, you will need to fill in any cracks or pitting before applying the new sealer. This will ensure a smooth and even finish to the final result.

To fill in cracks and smooth the surface, start by choosing the right product. You will need to purchase a concrete crack sealer from a hardware store. Once you have your sealer, follow the manufacturer's instructions for application. Apply the concrete crack sealer to the affected area and use a putty knife to smooth it over, creating an even surface. It is important to follow the manufacturer's directions regarding dry time, as this can vary depending on the product.

Allowing the sealer to dry completely before proceeding to the next steps is crucial. Depending on the product, this could take several hours or even a full day. Refer to the manufacturer's instructions to determine the appropriate drying time for your specific sealer. Once the sealer has dried, you can proceed to the next steps of the resealing process, such as applying a concrete dye or the new sealer itself.

By taking the time to fill cracks and smooth the surface of your concrete patio, you will create a uniform base for the new sealer to adhere to. This will help ensure that your resealing project is successful and that your patio looks its best.

Apply two thin coats of new sealant

To apply two thin coats of new sealant, follow these steps:

Firstly, check the weather. Sealer needs to be applied in dry conditions and temperatures above 50°Fahrenheit. The drying process can take up to three days, so ensure you have ample time.

Before you begin, ensure your patio is immaculately clean and fully cured. If your patio is new, wait at least a month before applying the sealer. Use a brush for edges and detailed work, and a sprayer for larger areas. Avoid creating puddles by ensuring thin, even layers.

Apply the first coat and wait at least two hours before applying the second. Check your sealant can for specific drying times. When applying the second coat, brush it on at right angles to your first coat.

Finally, allow the sealant to dry. Do not step on or place objects on the patio until it is completely dry.

Allow sealant to dry

Allowing your sealant to dry is a crucial step in the resealing process. The drying time will vary depending on the type of sealer used, the temperature, humidity, and dew point.

Acrylic concrete sealers, for example, typically require 48 hours to dry completely, although they can be walked on after 12 hours if necessary. Silane and siliconate sealers, on the other hand, can be walked on after just 30 minutes but should be left undisturbed for up to 72 hours to become fully functional. Silicate concrete sealers have a similar drying time, being safe to walk on after an hour but taking up to 90 days to fully react with the concrete.

Epoxy and urethane coatings take the longest to dry, with a full cure taking anywhere from 1 to 7 days. This is the time it takes for the coating to fully harden so it can withstand vehicle and forklift traffic. If you're planning to use your patio before this time, light foot traffic is usually fine after 24 hours.

It's important to note that applying a sealer to a damp surface can cause a "blushing" effect, resulting in a cloudy appearance as moisture becomes trapped inside the sealer. Therefore, it's crucial to ensure that your concrete patio is completely dry before applying the sealer and to allow ample time for the sealer to dry before using the patio again.

Additionally, when resealing a concrete patio, it's essential to choose the right type of sealer and apply it evenly. An uneven application can result in patchy areas that look unprofessional and offer inconsistent protection. Taking your time and working methodically will ensure a uniform coat that protects your patio evenly.

Frequently asked questions