From Dan on August 5th, 2008 in Concrete, Tools and Tips
You may be surprised at how dirty your concrete has become, even if you don’t see any drastic stains. Dirt slowly accumulates on the porous concrete, so slowly that it often goes unnoticed until it is cleaned, and the difference can be amazing to the previously unaware homeowner. It is a good idea to schedule regular cleaning of concrete surfaces to prolong the life and look of your driveway, patio, or other surface.
The quickest and easiest method available for cleaning concrete is power-washing. High-pressure washers can be rented locally. Hot, pressurized water alone can do wonders for your concrete but often, especially for common oil, grease, or rust stains, chemicals can be combined with the water to lift and eliminate the stains. Cleaning agents should be available at the same place you rent the power-washer.
For oil and grease stains, perhaps the most common of driveway stains, use an alkaline degreaser. The hot water works to lift the oil from the concrete and the degreaser emulsifies the oil, allowing it to be washed off the surface.
Rust stains will require something a bit more powerful because of how deeply rust penetrates into the pores of the surface. Try cleaners containing oxalic acid combined with the power-washing.
Hot vs Cold Water
In the kitchen, hot water cleans better than cold water. And the same goes for power-washing and concrete cleaning. However, cold-water power washers are cheaper, lighter, and easier to use than hot-water power-washers. For most residential applications, cold water washers will work just fine but it will likely take longer to lift any stains. For severely stained concrete, or large, time-consuming jobs, you might consider hiring a local contractor who will have heavy duty, hot-water washers to complete the job quick and painlessly.