How To Remove Oil Stains From Concrete Garage Floors

One of the most common challenges encountered when Acid-Staining Garage Floors is the effective removal of motor oil in the driveway—the same issues arise with vegetable oil and animal fats that spill around outdoor grills and eating areas. Depending on the severity of the spill, oil that builds up over time can be very challenging to remove. Unless properly cleaned, oil will prevent Acid Stain, Concrete Stains and Sealer from penetrating the concrete.

First Things First

Because oil penetrates deeply into concrete, it’s essential to clean up a spill the moment it happens. Once oil enters porous concrete, nothing else can penetrate or adhere to its’ surface. If nothing is done to clear the oil, acid stain won’t take to the concrete and the sealer will likely bubble up or flake off after application. Not the desired outcome.

How To Know If You Have Oil at the Concrete Surface

The best way to determine if you have a stain requiring additional cleaning is to spray water across suspected areas. Spotting either of the following means you likely have an oil stain:

  • Water “beads up”
  • Water displays a “rainbow sheen”

Sometimes an old oil stain is visible but nothing remains at the concrete surface. If it passes the water test, it should be ready to stain.

Cleaning Oil From Your Concrete

Clean the concrete with a solution of Concrete Cleaner & Degreaser and water. Observe after cleaning whether water is beading up over any oil spill area. If there is no indication of a spill that needs attention, rinse the concrete thoroughly, allow to dry and proceed with staining.

If some evidence of beading or oil sheen persists, we recommend the following procedure:

  • Purchase a bag of “oil absorbent,” such as Oil Dri™
  • Create a mound of the material to cover the spill area
  • Pour a solvent like, “Odorless Mineral Spirits” or “Xylene” over the mound and leave until completely dry (Solvents can be purchased at your local DoitBest Hardware Store)
  • Once the solvent has evaporated, sweep the oil-dry away and dispose of responsibly
  • Clean again with the degreaser and water solution, rinse and look for beading

Successful removal will not reveal a perfect looking concrete slab; instead, some signs of staining will remain beneath the surface. In most cases this should not affect acid staining.

What If I Continue to See Water Beading & Rainbows?

Sometimes it will take more than one application to remove the oil from the concrete surface altogether. Repeat the steps until the beading and sheen disappear. The process may need to be repeated up to 4 times if the oil stain is particularly large or very old. Vegetable oil, oddly enough, is one of the most difficult oils to dissolve and sometimes requires mechanical abrasion using a floor sander and a 50-100 grit pad to resolve finally.

What To Do About Unsightly Oil Stains That May Be Ready to Color But Can Still Be Seen in the Concrete?

  1. Use our guide to Complete The Floor Prep Work before placing an order for coloring product.
  2. Select an Acid Stain or Antiquing Stain Color that will help mask the appearance of the oil so it will be less noticeable overall.

Keep in mind that with a few exceptions, most concrete is not visible below patio furniture, barbecues, or other things that make oil stains less apparent when you begin “living” on the concrete.

If you have more questions, or for more helpful DIY tips, call one of our expert technicians Toll Free at: (877) 255-2656 or (405) 275-6657

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