Will Concrete Sealer Prevent Oil Stains?

Concrete sealer can certainly prevent oil stains from setting into concrete. In this blog, we will cover how concrete sealer works, how oil soaks into concrete, and situations where concrete sealer may not prevent oil stains. 

How concrete sealer works

Concrete sealer is a chemical product that initiates a chemical reaction. The different compounds in the sealer react with the inorganic compounds found in concrete to fill the pores on the surface. Fortunately, this does not completely clog the concrete and the surface will remain permeable to water vapor (i.e. breathe). This prevents excess moisture buildup under the concrete and will allow pressurized water to enter the surface while preventing other materials, like oil, from getting into the pores. 

For more info on this, read our article What is the Point of Having My Driveway Sealed?

Concrete sealer being applied in Verona, WI

How oil soaks into concrete

Concrete is a porous surface and, when left unsealed, it can absorb different materials and hold them over the long term if they don’t evaporate. Oil is a common material on that will soak into concrete and stay due to its low viscosity (allowing it to soak into the concrete) and inability to evaporate at normal outside temperatures.

Common reasons for oil spilling onto concrete are leaking parked vehicles, grease from a grill, and oil changes on small equipment getting spilled. When oil is spilled onto concrete, it will take a while to soak in. If you spill oil on concrete it should immediately be dabbed, not wiped, to try and remove as much of the oil as possible.

For more info on this subject, read our article on Oil Stain Removal In Concrete here.

Situations where concrete sealer may not prevent oil stains

Concrete sealer will not always prevent oil stains from occurring. If the sealer is old, the surface is damaged, or the sealer was applied incorrectly, oil stains could happen to your concrete.

The sealer should be reapplied every 2-5 years to maintain its usefulness. This primarily varies due to the specific product being applied. Follow the manufacturer's instructions to get the best result.

If the concrete is damaged, that exact area will likely not be sealed as well (or at all) in comparison to the undamaged area. If there is chipping in the concrete before application of sealer it will likely still not absorb oil but the increased surface area could lead to improper coverage of the sealer. 

Incorrect application of concrete sealer can happen in a myriad of ways with the most common being underapplication. Not all concrete sealers require the same application and careful measurements should be made when purchasing sealer for your driveway to ensure you have enough.

Concrete sealer often appears milky during application and becomes transparent as it cures

Concrete sealing is not an easy or simple task and requires knowledge, skill, and experience. If you need help with your concrete sealing project, reach out to the experts at EcoWash for help.