Oil & Grease on Concrete
Oil & grease on concrete appear as darkened patches or blotchy stains caused by absorption into the surface. Because concrete is porous, oil-based substances can penetrate below the surface and create long-lasting discoloration.
What’s Happening
Concrete is made from cement and aggregate and contains microscopic pores throughout the surface. When oil or grease sits on concrete, it can soak into those pores and darken the surrounding area.
Unlike etching, which lightens or roughens the surface, oil staining typically:
- Darkens the concrete
- Creates irregular blotchy patterns
- Becomes more visible when dry
- May spread slightly beyond the original spill
Common sources include:
- Automotive fluids in garages
- Cooking oil near outdoor kitchens
- Restaurant or commercial kitchen grease
- Machinery lubrication
- Trash bin leakage
If the concrete is unsealed, absorption happens quickly. Even sealed concrete can stain if the protective layer has worn down.
If the affected area appears lighter or rough rather than darker, review Etch Marks on Concrete to rule out chemical surface damage.If the area appears dark rather than lighter, review Oil & Grease on Concrete to rule out absorption staining.
What To Do
If your concrete is sealed…
Clean the area with a pH-neutral cleaner and allow it to dry completely. If the darkened area disappears when wet but returns when dry, oil has likely penetrated through a weakened sealer. A poultice formulated for oil removal in concrete may help draw the stain out. Once the area is properly treated and fully dry, resealing may be necessary to restore protection. Avoid aggressive scrubbing that could strip remaining sealer unevenly.
If your concrete is unsealed…
Blot excess oil immediately without spreading it. Clean with a neutral cleaner and allow the surface to dry fully. If staining remains, a concrete-safe degreasing poultice may help extract embedded oil. Multiple applications may be required depending on stain depth. Avoid using harsh acids, as they can etch the surface without removing the oil.
If you’re not sure if the concrete is sealed…
Clean gently with a neutral cleaner and observe how the surface behaves when wet versus dry. Persistent darkening after drying typically indicates absorption. Professional evaluation may be recommended for large or deep stains, especially in highly visible areas.
If the discoloration appears orange or reddish rather than darkened, review Rust on Concrete to rule out oxidation.
What NOT to Do
- Do not use acidic cleaners to remove oil stains.
- Do not pressure wash aggressively in a way that damages the surface.
- Do not use abrasive grinding without blending surrounding areas.
- Do not seal over active oil stains.
- Do not ignore recurring staining in high-use areas.
When to Call a Professional
Call a professional if oil stains remain after appropriate treatment or if the affected area is large and visually disruptive. Deep oil penetration may require specialized extraction methods or surface refinement. Professional treatment ensures uniform appearance and proper resealing when necessary.
Safety Equipment
- Protective gloves
- Eye protection
- Respiratory protection when working around concrete dust
- Adequate ventilation when using cleaning products
Prevention
- Clean spills immediately.
- Use mats or drip trays in garages or cooking areas.
- Maintain appropriate sealing for interior concrete.
- Avoid allowing oil to sit overnight.
- Implement routine cleaning in high-use environments.
Disclaimer:
The information provided through Surface IQ is for general informational purposes only and is not a substitute for professional evaluation or service. Surface conditions, materials, finishes, and installation methods vary, and results cannot be guaranteed.
NextGen Surface Care assumes no liability for damage, injury, or loss resulting from the use or misuse of this information. Always test any treatment in an inconspicuous area before full application. Follow all product instructions carefully and use appropriate personal protective equipment (PPE) with proper ventilation.
For delicate, valuable, or antique surfaces—or if you are unsure about the material, finish, or condition—consult a qualified stone care professional before attempting any treatment.