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Pressure washing concrete

So, you want to pressure wash some concrete. Must be easy right? After all, it is only concrete and how tough can it be to screw that up right?

Before you start power washing any concrete, there are a few techniques and things you will want to keep in mind. We’ll start out with what type of tip you’ll need to be using the get the best results out of pressure washing your concrete.


In case you’re not familiar with the different tip sizes, there are tip sizes for basically every washing job you could think about performing. The tips change the angle of water as it comes out of the end of the pressure-washing nozzle at the end of the wand.

For concrete, the best nozzle is probably the 15 degree. It is the least amount of fan next to the straight stream. Rarely do I use a straight stream for anything, except maybe knocking down wasp nests from far away.

Be careful when you start spraying and pay close attention to the area your hitting with the high pressure washer. Many times, there will be a slight crack in the concrete which if hit just right with the pressure washer, can turn into a big crack in a hurry.  Always start with the spray pointed away from the spraying service and move it into place after you’ve started the spay with the trigger pulled.


I can be sort of lazy, so I really like the detergents that come in the dissolvable packets. I use the Green dissolvable packets from Home Depot. They smell really nice and work fairly well at cutting through grease. You can also come up with your own home made detergent. Depending on what you’re trying to get off the concrete will determine what the of detergent you want, if any. Most often, the concrete I’m power washing is simply my garage and driveway. I love clearing out my garage and going to town with the pressure washer. And for this, the simple soap type of detergent works fine. Leaves the garage smelling good also.

One thing to think about when pressure washing concrete, is that hot water washers work the best. Although they can be a bit more expensive, even to rent, they will cut through the grease a lot better than cold water. Think about the elements that need to be present when washing and how they all work together, heat, pressure, and chemical.

If the concrete or masonry you intend on washing is full of cracks and falling apart, you may want to think twice before going at it with a pressure washer. Unless this is part of your demo process. If you do really need to clean it, try using at least a 40 degree tip which will put less pressure on the concrete surface.

Always start on a little spot to see what effect your washing is having. I generally like to clean a small spot about the size of a basketball then let it dry for 10 or 15 minutes to make sure it’s not damaging the surface. This is especially if you’re washing concrete with seams or things like floor tiles.


How to Pressure Wash A Deck

We talked a little in another post about the proper way to use pressure washing equipment to wash a deck, but we didn’t go into many details. Here we are going into a little more detail on the proper way to power wash your deck.

I recall the first time I discovered a pressure washer, I thought it was the coolest thing and set out to wash everything in my neighborhood! One thing I found out is that a pressure washer can seriously damage wood, as in my friend’s wood fence!

There are just as many cleaning solutions for decks as there are types of sprayers, so chose the one best suited for your needs. Remember there are different kinds, cleaning solutions (detergents), bleaches, and chemicals. So check with your local hardware store or where you rent your pressure washer to determine which solution is best for your project. Moreover, always be sure to read the label for proper mixing and handling. Always remember the basics of pressure washing in that the process is a mixture of water, heat, and detergents/cleaners so let the process work for you. Do not just try to power everything off with water pressure, let the cleaner do its job! One product which I’ve used and like is the Karcher Pressure Washer Deck SoapPac This comes in 12 pack pouches which are easy because you just throw them in your bucket and they dissolve.

Let us now look at pressure. A good rule of thumb for PSI levels when power washing a deck or wood is no more than 1500 PSI (pounds per square inch). Although, always be cautions however because even this pressure can damage soft wood. When spraying wood, you want a fan width to be 40 to 60 degree’s which means you’ll want a 40’ or 60’ degree tip. Always start the sprayer with the tip facing away from the wood and move in to the surface. Do not start with the tip directly on or near the surface.

Most often the process of cleaning and pressure washing your deck will require scrubbing; usually with some type of cleaning agent. It is a good idea to use a brush made with synthetic bristles. Just like with other cleaning agents, some chemicals will eat away at the bristles of the brush and cause more of a mess than you started with. Again, read the instructions for the cleaning agent to be sure you are applying it correctly. Some cleaning solutions can damage your deck if you allow them to dry, deck1so always have a hose handy to wet the deck down while brushing and applying the cleaner.

When spraying the deck, sweep from side to side and use a feathering technique. This is similar to power spray paining. You will notice that you can tell where you have started and stopped pressure washing; the wood will have a different color.  Feathering is one technique to avoid this by overlapping the area you previously covered. Start each stroke with the pressure washer nozzle just before the end of the previous stroke. Always go with grain of the wood also to get the best results.

This is a quick overview of how to power or pressure wash your deck. We touched on the “feathering” technique but there are many other techniques for spray patterns. We will go over some others in up and coming posts. Stay tuned for those!