The quick answer is yes, power washing can degrade a concrete surface. You can notice visible damage from water pressure at the level at which even light-duty power washers can operate. Therefore, if you aren't careful, you can cause irreversible damage to your driveway or patio.
Most people believe that concrete is solid and almost invincible. However, using a pressure washer with the incorrect tip or using too much pressure or a combination of the two can etch concrete.
Our recommendation ranges from as low as 3,000 PSI to as high as 4,000 PSI. But, there are quite a few factors at play influencing your ideal PSI rating.
Generally, you'll want your concrete driveway pressure washed at least once a year. This lets you treat sunbaked dirt, grime buildup, and stubborn oil stains, making regular cleaning in between professional washes much more manageable. Of course, you can always schedule extra pressure washing services as needed.
To get the job done right, you need a pressure washer rated at least 3,000 PSI with a flow rate of at least four gallons per minute (GPM). Hotsy Water Blast can provide you with an electric, gasoline or diesel pressure washer that delivers sufficient power.
Medium Duty 2000-2800 PSI
This classification ranges from as low as 2,000 PSI to as high as 2,800 PSI. You can use a medium-duty pressure washer for almost any surface. They're great for cleaning concrete, brick, and wood.
Once the pressure washing is complete, it is important to wait until the surface is completely dry before applying any sealant. Depending on temperature and humidity levels, this process can take anywhere from 24-48 hours.
An effective pressure wash cleans the pores of your concrete. Make sure to apply concrete sealer after pressure washing.
Concrete cleaning calls for powerful pressure washers featuring high pressure levels of 3000 PSI. However, if you will be using the power cleaner to maintain a range of surfaces in addition to concrete, choose one with adjustable pressure levels and set it to about 3000 PSI when you need to clean concrete.
Concrete typically takes 24 to 48 hours to dry enough for you to walk or drive on it.
5,000 PSI. Used in special construction applications, including some large-scale commercial and industrial properties, 5,000 PSI can withstand heavy impact and extreme wear and tear.
Powerful pressure washers with too much PSI will damage concrete when power washing. Most residential driveways require no more than 3000 to 3500 PSI for proper and thorough concrete washing. Heavy-duty commercial pressure washers and other power washing equipment are too strong for the average residential driveway!
The downside to using pressure washers is that they tend to cause damage to surfaces that are too delicate. In addition, the high pressure of the water spray can cause damage to surfaces you don't intend for it to reach, such as brick or stone surfaces.
Dish soap and water: Dish soap is a degreaser, and it works well to clean oily and grimy concrete. Create a cleaning solution of warm water and few drops of dish soap and apply it to the surface. Let it sit for a while, then mop the patio and rinse it with fresh water. Repeat the process as many times as needed.
A higher psi means a given concrete mixture is stronger, so it is usually more expensive. But these stronger concretes are also more durable, meaning they last longer. The ideal concrete psi for a given project depends on various factors, but the bare minimum for any project usually starts around 2,500 to 3,000 psi.
A strength of 4,000 psi (pounds per square inch) after a one month cure is the industry minimum for concrete driveways, slabs, and sidewalks. However, 4,500 psi as the ideal. According to guidelines published by AsktheBuilder.com, a home foundation requires a thicker pour of 8-10 inches and a psi of 3,500-4,000.
Ideal Concrete Strength For Common Structures
So, what is an ideal concrete PSI for common structures? Most residential projects, such as sidewalks and driveways, require 2,500-3,000 PSI. Structural components like beams and footers require a PSI of 3,500-4,000.
You can power wash concrete all year as long as the temperature is about 40 degrees Fahrenheit. Most homeowners and businesses prefer to do it in the spring or summer to reduce the spread and growth of algae and mold. It also reduces pollen, which can affect allergies.
Properly curing your concrete improves strength, durability, water tightness, and resistance for many years. The first 7 days after installation you should spray the slab with water 5-10 times per day, or as often as possible. Once the concrete is poured the curing process begins immediately.
An unsealed concrete floor is going to be more reactive and sensitive to changes in temperature. It will freeze in cold climates and expand in warm ones. This can cause crumbling, chipping, and cracking.
After the concrete has dried for at least 24 hours, you can effectively apply a concrete sealer. A sealer helps prevent future stains and potential damage from products like ice salts.
Dark Spots on Concrete After Power Washing
If you notice dark spots on concrete after pressure washing, it's likely that the surface is damaged and that the top layer is washed off. This type of damage is prevalent in slabs that are topped with a screed with a different color from the base concrete.