A lot of people will ask “why do I need to wash my concrete?”.
The number one reason isn’t for appearance, it is actually safety. In humid climates like League City Texas (located south of Houston) the humidity is high here and our driveways collect algae very quickly. In the morning when it is still misty outside it makes the concrete incredibly slippery which can cause a slip or fall. This is especially important for commercial entities that want to protect themselves from liability against injuries. Here is a video on what cleaning organic growth should look like for concrete
But other than algae other things can also make the concrete slippery.
Calcium: Calcium is commonly found near pools and can be a white, brown or gray substance that makes concrete especially brick slippery causing a safety hazard for a pool environment. This cannot be cleaned simply just by pressure washing and requires several other steps to clean properly.
Rust: This is really commonly found when someone has an irrigation system that is automatic or when iron fertilizer is used for the lawn. This can also create a slip hazard and requires more than just pressure washing, like calcium it needs several other steps to be able to remove safely. Here is a video on how we remove rust from concrete (note after this video was taken we had to spray a degreaser to neutralize the acid that removes the rust because it stays active until that occurs, the process is identical for removing battery acid)
Battery Acid: Battery acid stains look like rust, but it is not rust. It is actually from moisture settling on batteries (very common with golf carts) and the runoff from the battery lands on the ground and creates an orange slippery surface that can’t be removed by just pressure washing.
Oil: Oil and hydraulic fluid are commonly spilt on driveways and are extremely hard to remove. In most instances oil can’t be removed at all and at best can be lightened with hot water and degreaser applications. Oil is a very common cause for slips on concrete and should be removed immediately. The longer they sit on the concrete the worse the stain becomes.
Grease: This is commonly found after a holiday when people are cooking outside or using an outdoor fryer. This can mostly be removed with pressure however, it will still be slick and require either heat or a degreaser being applied to remove. This is extremely common at restaurants and most restaurants have a regular maintenance schedule for cleaning this to prevent injury of guests and employees. Here is a video on what cleaning grease looks like
Paint/Graffiti: There have been several lawsuits against commercial entities for paint being placed on the wrong areas creating a slippery surface and someone developing an injury from slipping on the painted surface. Paint and graffiti can reduce the coefficient of friction on concrete and should be removed when it is in a place it was not intended to be. It is also recommended on commercial entities that if you have a painted sidewalk that there be a handrail provided to prevent slips for pedestrians. Like many other things paint requires more than just pressure to remove and even with hot water will not entirely remove paint or graffiti. We have a video of us removing spilt paint after applying graffiti removal.
Something to consider is sometimes cleaning the concrete is more than just about a safety hazard. In the photo attached to this article we walked by this very slippery grease spill that was in a heavily used parking lot. And one thing we noticed outside of the fact it was slippery is how bad it smelt. When you own a restaurant do you want the first thing a customer smells is what stinks outside prior to entering your establishment? Marketing involves using the senses people use to associate with a brand. Brand by smell is a very critical branding type a business has. Think about when you enter Bath and Body Works, don't you have a smell you associate with this business when you enter? You don't want them to associate your brand with a smell of sewage, it will create the wrong impression for your audience. So keeping concrete clean is also important when considering what you want your property to smell like (or not smell like).
One thing we do is when we clean a residential driveway we spray a soap application in the end to create a more even clean on the surface. This also prevents the algae from growing back as fast. So whether you are planning on doing this project yourself or hiring a professional, it is great to know this since concrete is one of the most expensive items on your property.
Not all power washing is the same. Here’s what property owners and managers must know before hiring a contractor to clean your concrete.