How to Restore Stained Concrete
Stained concrete has become a common sight around homes and businesses. Unfortunately, stains such as oil or grease left behind from food spills can be very difficult to remove. If you don't want to spend thousands of dollars replacing your driveway, consider using a stain removal kit instead.
Concrete is a mixture of cement, sand, water, and aggregates (such as gravel). When poured into forms, these materials are mixed to create a solid mass that can then be cured at room temperature or heated to harden. To prevent further staining, concrete floor surfaces can also be sealed with epoxy sealers or special coatings.
"Oil stains" are particularly problematic because they usually contain both organic solvents and oils. The presence of either component can cause serious damage to concrete. Fortunately, several ways to clean outdoor concrete won't require expensive chemicals or equipment.
Restoration of Stained Concrete Floors
Stains on concrete floors can occur in many different ways. Some are caused by using certain cleaning products, while others are due to improper maintenance. Whatever the source of the problem, it's important to know how to treat and repair stained concrete properly.
The first step in restoring stained concrete floors is to determine your type of stain. Oil-based stains must be removed before any other steps can be taken. Once this is done, the next step is to apply a penetrating sealer to the surface. A topcoat sealer should follow this.
If the stain is not oil-based, then follow the same process but skip the application of the penetrating sealer. Instead, apply a protective coating over the entire area.
Once all the above steps have been completed, you'll need to wait for the stain to dry completely. Afterward, you can begin applying a new finish to the concrete space.
The Process of Concrete Staining
When concrete is first poured, it's called "green." This means it hasn't yet hardened completely. It's soft enough for workers to walk on without damaging the surface. After it's been set, however, it becomes harder and more durable.
After it's fully cured, concrete stains can be colored with various pigments. Some colors are permanent, while others fade over time. You can choose between different types of finishes depending on what kind of look you prefer.
You can apply color directly to the freshly-poured concrete or wait until after it's cured before applying the finish. Once the concrete is dry, you can apply the finishing product.
Acid stains are commonly found on concrete floors. They come in two varieties: acid stains and acid etch stains. Acid stains are applied directly to the concrete. They're typically made from sulfuric acid, which reacts with calcium hydroxide in the concrete to produce a dark brownish tint.
Sulfuric acid is corrosive and dangerous. It can burn skin and eyes and eat through steel reinforcement bars. If your home has a garage door opener, ensure it's protected against contact with this type of stain.
Acid stains are easy to apply. Just pour some onto the concrete and allow it to sit for about 15 minutes. Then scrape it off using a putty knife or similar tool.
Etch stains are less common but just as effective. They're applied to the concrete after it's been partially cured. They're made from hydrofluoric acid, which dissolves the calcium hydroxide in concrete. When the concrete dries, the resulting pattern looks like tiny pits.
Etch stains are more difficult to apply than acid stains. You'll need to mix the acid with water and then apply it to the concrete. Wait at least 24 hours before scraping it off.
Urethane for Industrial Coating
Urethanes are popular coatings for industrial building floors. They're usually sprayed on top of existing paint jobs. Urethanes protect against weathering and corrosion. They're also resistant to scratches and dents.
Urethanes are available in several different forms. One of the most common is spray urethane. Spray urethane comes in two main varieties: clear and semi-transparent. Clear urethanes are used when you want to see the underlying substrate. Semi-transparent urethanes are used if you don't want to see the substrate.
To apply a urethane coating, follow these steps:
1. Clean the area thoroughly. Use soap and warm water.
2. Apply primer. Primer helps prevent staining by sealing any bare spots on the concrete.
3. Mix the urethane. To do so, add the appropriate amount of catalyst to the urethane base.
4. Coat the area. Using an airless spray gun, spray the mixture onto the concrete. Allow it to dry overnight.
5. Seal the area. A sealant will help keep the new coating intact.
6. Finish up. Remove dust and debris that may have accumulated during application.
7. Let it cure. The final step is waiting for the urethane to harden completely. This could take anywhere from one day to three weeks.
Concrete Polishing Finish
A concrete polishing finish adds shine and protection to concrete surfaces. It's often used on driveways, sidewalks, patios, and pool decks. Concrete polishers use abrasives to remove surface imperfections and dirt.
There are many types of concrete polishes available. Some are designed for specific applications. For example, there are concrete polishes for driveway pavers, sidewalk pavers, and driveway slabs. Others are general-purpose products that work well on all kinds of concrete.
The best way to choose a concrete polish is to look at its ingredients. Look for ones that contain no silica sand. Silica sand is abrasive and can damage concrete.
Some finishes include additional chemicals. These are called "multi-purpose" products because they can be used on concrete and wood.
What Stain Color Should you Use for Concrete Surface?
Stains come in hundreds of colors. There are even some that match your home's exterior color. But what should you stain your concrete?
Consider using a deep red or orange if you're looking for something bright and bold. If you prefer a muted tone, try a light gray or blue. Whatever color you pick, make sure it complements the rest of your house.
Consider using dark brown if you'd like to go with a neutral color. Dark browns tend to blend in better with other colors.
You can also opt for a contrasting color. Try a lighter shade of green or yellow. Or, if you want to stand out, go with a bright white.
Concrete Stain & Sealer Paint Products
When choosing a concrete stain, think about how much time you'll need to get the job done for the layers. You might want to start with a product that requires less maintenance.
For instance, epoxy stains require only one coat. Epoxies are easy to apply. They're durable and long-lasting. However, they must be applied before the concrete has fully cured.
On the other hand, acrylic stains can last several years without needing to be reapplied. Acrylics are more flexible than epoxies. That means they won't crack as easily.
Another consideration is whether you plan to paint over the concrete after applying the stain. If you do, you'll need to select a paint that matches the color of the concrete.
Residue and Chemicals from Concrete Sealers
Sealers are typically made of latex. Latex is an oil-based material. When applied to concrete, it dries quickly. Once dry, it creates a protective barrier against moisture.
Latexes are usually clear or tinted. Tinting makes them easier to see when they've been applied.
If you plan to paint over your concrete sealer, you'll need to find a paint that matches the sealer's color. Otherwise, the two will clash.
If you don't plan to repaint your concrete, then you may not have to worry about matching the sealer's color to the existing concrete.
A few things to consider when selecting a concrete sealer:
• How thick does the sealer need to be? Thicker seals provide greater protection.
• What type of finish do you want? A flat finish provides a smooth surface. It's ideal for driveways, sidewalks, and patios.
• Do you plan to use a waterproof sealant? Waterproof sealants prevent water from penetrating into the pores of the concrete. This helps keep the concrete from becoming porous.
• Is the concrete sealed already? If so, you may not need a sealer at all.