Concrete is tough, but it’s also porous. Without a protective topcoat like epoxy, a concrete floor will readily absorb paint, oil and other liquids several millimetres deep into its surface. Careless driving on a concrete surface can also result in tough-to-remove tire marks.
The good news is, it is possible to get most stains out of a concrete floor if you take the right approach.
There are several ways to go about removing paint, oil and tire marks from a concrete floor. For smaller stains, you can usually start with the low-tech approach and step it up if necessary; for tough jobs, you might want to bring out the blasting guns from the beginning.
Removing Paint from a Concrete Floor
The fresher the paint, the easier it is to remove. But even a long-hardened stain doesn’t have to be there for good. With the right tools and techniques, it is possible to remove paint from concrete’s porous surface.
Method 1: Media Blasting
Contrary to popular belief, it is safe to use a blasting gun indoors with proper choice of techniques and equipment and blasting media. Media blasting can completely remove large paint stains from a shop, garage or factory floor without damaging the underlying concrete. Though the process does leave behind some dust and residue, the floor underneath is a clean slate for sealing or re-painting.
Method 2: Floor Grinder
A floor grinder with a diamond grinding cup wheel can effectively scrape off the entire top layer of a concrete floor, including paint stains. For small stains, a hand-held angle grinder can also do the job. However, this method requires that you re-finish the area with fresh cement, as it will leave behind a rugged surface that will quickly accumulate dirt and debris.
Method 3: Paint Remover
Paint remover (or paint stripper) is a compound designed to remove paint and clean the underlying surface. Although some manufacturers have introduced non-toxic paint removers (such as soy-based gel products), most products on the market contain harsh chemicals. You should only use a chemical paint remover in a well-ventilated area while wearing safety glasses, rubber gloves and rubber boots.
Removing paint from a concrete floor using paint stripper is a surprisingly arduous process (you cannot simply pour it on and wait.) As a result, this method is best used for paint stains with a small surface area.
The basic process:
- Thoroughly clean the area with soap and water to remove any loose dust or debris. For stubborn dirt, use a stronger cleaner like trisodium phosphate (TSP).
- Remove any loose paint with a wire brush or putty knife and sweep it away from the area.
- Apply the paint remover. The correct type of remover depends on the type of paint in question; when in doubt, use an oil paint stripper.
- Let the remover to work its way into the concrete floor. Check the manufacturer’s instructions on how long to wait.
- Wearing protective gloves, scrub the stain with a wire brush or putty knife to remove the loosened paint.
Depending on the depth of the stain, this process may have to be repeated two to three times in order to completely remove the paint from your concrete surface.
Removing Oil Stains from a Concrete Floor
Forgot to put down a catch pan during your last oil change? It happens, and it’s not pretty. Oil is among the most stubborn stains to remove from concrete, but it’s important to do, because that oil can eventually seep back to the surface and ruin your next paint or sealing job.
Method 1: Detergent
If you notice the oil stain while it’s new, it may be possible to remove through the application of a strong detergent, warm water, a stiff brush and lots of elbow grease. Start by blotting the stain with a rag or paper towel to absorb loose oil (dab, don’t rub, to avoid spreading it). Next, apply a detergent and scrub the stain with a brush soaked in warm water.
Method 2: Absorbent Material (Poultice)
A poultice is an absorptive material (like sawdust or kitty litter) saturated in a solvent (like acetone, xylene or lacquer thinner) that is placed on the concrete surface and covered in plastic wrap. Through the process of osmosis, the concoction breaks down the spilled oil and ‘pulls’ it out of the floor. It’s time-consuming, but it works, especially for small, fresh stains that haven’t had time to set.
Method 3: Media Blasting
For serious oil stains that have stood the test of time, media blasting is your best bet for removal. A blasting system uses pressured air (and water, in the case of wet blasting) to propel an abrasive material at the floor and strip off surface-level stains. Media blasting is gentle on the underlying concrete surface (which, though durable, is porous and easily scratched), making it ideal for property users who plan to paint or refinish the floor afterward.
Removing Tire Marks from a Concrete Floor
A driver came in fast and didn’t quite stick the landing; now, you’re stuck with tire marks on the floor. Fortunately, it doesn’t have to be there for good. Removing tire marks from concrete is a simple task.
Method 1: Pressure Washing
If the concrete floor is rated for pressure of 4000 psi, pressuring washing is an option for removing rubber markings. Set the water to a pressure of 3000 psi and a temperature high enough to produce steam.
Method 2: Media Blasting
Passing over the floor with a blasting gun can take the tire marks right off. Since the rubber will not have penetrated the concrete as deeply as paint or oil, it should take only a light touch with a fine blasting media to remove tire marks from the floor.
Method 3: Degreaser
Soak the tire marks in an industrial-strength degreaser (available at most hardware or auto supply stores). After 10 minutes of soaking, scrub using a stiff-bristled brush. Clean the loosened rubber with a sponge and warm water. Be sure to let the area dry completely before parking on it.
Restoring Industrial Concrete Floors
Media blasting is an effective tool for restoring stained concrete floors to their original glory, but like any tool, it’s most effective in the hands of a professional. The experts at Sign LITE are happy to help when it comes to removing paint, oil or rubber from your concrete floor. Get in touch to learn more about our industrial media blasting services in Southwestern Ontario.