How to Pressure Wash Concrete – A Guide
If you’re a house owner in the Pakistan, you have some concrete surface on your property. Most likely a driveway, but also perhaps a wall or a pathway. Whatever the surface may be, it will get dirty over time. That‘s when your power washer comes in handy.
With a pressure washer, cleaning concrete surfaces is as easy as counting 1,2,3, if you know what you’re doing.
Pressure washing concrete is highly recommended, as it effectively cleans both the surface and the pores. But how do you do it?
Don’t worry! Whether you’re an experienced pressure washer or a complete beginner, this article will guide you through the process of pressure washing concrete and provide useful tips for enthusiasts at any skill level.
What Types of Concrete Are There?
Concrete is primarily composed of three key ingredients: cement, sand, and construction aggregate. However, not all concrete is identical, and it’s important to recognize these differences. Various types of concrete possess unique properties, such as hardness and porosity.
While the standard 1:2:4 ratio of these ingredients is often used for driveways, there are many alternatives that may necessitate adjustments to your usual pressure washing approach.
1:2:4 Concrete
We’ll use 1:2:4 concrete (or simply “concrete”) as our primary material for this article. This formula consists of cement, sand, and construction aggregate in a 1:2:4 ratio. Concrete can either be mixed on-site or precast into blocks for assembly.
As such, concrete blocks should be treated like regular concrete, but with extra care for the edges, which are more susceptible to chipping when using a 0° nozzle, for example.
You might also find it challenging to clean the crevices between the blocks. In that case, it’s recommended to apply your detergent with a utility brush.
Ready-Mix Concrete
Ready-mix concrete(opens in a new tab) is pretty much just concrete that is premixed. It can be safely treated as 1:2:4 concrete.
Pre-Stressed Concrete and Reinforced Concrete
Be cautious! Concrete used in walls may be pre-stressed or reinforced, meaning steel components are added to its core.
However, this process only affects the interior properties of the material. The surface you’ll be pressure washing still behaves like regular concrete. The key point is that reinforced concrete doesn’t allow for any extra pressure when using your pressure washer.
Glass Concrete
Glass concrete is similar to regular concrete but includes recycled glass shards for a more stylish touch. This creates a decorative material perfect for facades and indoor flooring, as well as construction blocks for garden pathways that complement art deco homes and pool areas.
Keep in mind that while the glass shards are strong, they can still be brittle. So, it’s best to avoid low-angle tips when pressure washing, and any spot cleaning should be done by hand.
Lime Concrete
Lime concrete, or limecrete, is made by replacing the cement in regular concrete with lime. It’s often used for surfaces that are heated artificially and is a popular eco-friendly or decorative alternative to traditional concrete.
However, limecrete does have some drawbacks. It’s more porous, making it less durable and more susceptible to damage from high pressure, like using low-angle fan nozzles. It’s also important to choose detergents and sealants carefully, as they can affect the material’s porosity.
Decorative Concrete
Decorative concrete has become a popular choice for homes and public spaces. It refers to concrete that’s been enhanced through various techniques, such as acid staining, polishing, dyeing, stamping, and applying different polymer overlays.
With so many types of decorative concrete surfaces, each one is often uniquely crafted—sometimes by talented artists. Trying to list them all would be quite a task!
How frequently should I pressure wash concrete?
Concrete should be pressure washed and resealed every one to two years. You can clean it more often if it gets dirty. If you’re using a surface sealant, you should reseal after each cleaning. However, if you’re using deep-acting sealants like silicones, you don’t need to reseal every time you clean.
When is the best time to pressure wash concrete?
Before you pressure wash, check the weather forecast to avoid rain and direct sunlight. Plan to spend several hours on the task, including preparation. Also, remember to schedule resealing a few days after cleaning, once the concrete has dried.
What nozzle tip should I use for pressure washing concrete?
The nozzle on a pressure washer controls the force of the water stream. Whenever possible, use a 65° (soap) fan tip for applying detergents and a 40° or 25° fan tip for rinsing.
For spot cleaning durable concrete surfaces, lower angle tips can be used, but avoid 0° tips unless you’re experienced, as they can damage the concrete if misused. It’s safest to do spot cleaning by hand. If you prefer not to kneel, a 15° fan tip is the lowest angle you should consider.
What pressure setting should I use for concrete?
Concrete is quite durable and can handle high pressure settings. Its rough surface can make thorough leaning difficult at lower pressures. Many sources suggest using around 2000 psi, while others recommend up to 3000 psi. Therefore, we recommend a pressure range of 2000 to 3000 psi.
How to Pressure Wash Concrete
Now that we’ve covered the basics, let’s learn how to pressure wash concrete! While concrete is fairly forgiving, it’s important to do the job carefully and properly for the best results and your safety, as detailed below.
👉 Learn how to safely use your pressure washer and cleaning products.
Read all the manuals, flyers, and instructions for the equipment and products you’ll be using. Understand how to operate your pressure washer, follow safety guidelines, and know what personal protective equipment (PPE) is needed. Do the same for all cleaning products, including detergents and sealants.
Consider questions like: How long should the detergent sit? Are the detergent and sealant right for your concrete type? Is it safe to use the detergent in your pressure washer? What safety warnings are on the detergent label, and what precautions should you take?
👉 Test your Pressure Setting, Nozzles and Detergent
Before changing to a new setting or using a new product, always test it on a small, inconspicuous area of the surface to ensure it won’t cause damage or discoloration.
👉 Keep Your Tip Far from the Ground and Moving
Hold the gun about 2 feet above the surface and only lower it if necessary. Never get closer than 6 inches. Maintain this distance while cleaning, and always keep the gun moving. Avoid aiming the pressure washer at one spot for too long, especially with a low-angle fan tip!
👉 Apply concrete detergent and ensure it doesn’t dry
Apply concrete detergent according to the manufacturer’s instructions on the bottle, using either a 65° (soap) fan tip or a foam cannon.
Choose your detergent based on the level of dirt and stains on the concrete. Let the detergent sit for the recommended time, but don’t let it dry.
You may need to use a brush to clean corners or crevices, like those between concrete blocks. Once finished, rinse the entire surface thoroughly with a 40° fan tip. You can also use 25° or 15° fan tips where suitable, but be sure to test first.
👉 Let Concrete Dry Before Applying Sealant
Allow the concrete to dry, which can take up to 3 days. Use sealants only when needed, following the manufacturer’s instructions closely.