How to Pressure Wash Concrete

By eHow Home & Garden Editor

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Pressure washing is a great way to clean the grunge and grime from concrete driveways, pathways and patios. By using a pressure washer properly, you'll eliminate ugly oil stains and the danger that someone will slip on slick dirt or muck.

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Instructions

Difficulty: Moderate

Things You’ll Need:

Gloves
Pressure-washer approved chemicals (as needed)
Eye protection
Water source
Pressure washer
Power source (electric or gas)
Pressure washer accessories

Step1

Assess your project and develop a plan for cleaning that considers what direction the concrete surface drains and the location of fragile objects such as plantings and light fixtures. Work in the direction that water drains so you're not fighting gravity.

Step2

Select a nozzle, or tip, for the project which will also determine the PSI. The smallest angle, or opening, will deliver the most power. Most manufacturers suggest a higher PSI of 3000 or more cleaning concrete and most models include nozzles specifically for cleaning concrete; consult the owner's manual.

Step3

Attach any accessories when you connect the nozzle.

Step4

Put on protective eyewear and gloves before starting your pressure washer. Also, check that all connections are tight; a loose nozzle can become a projectile that can hurt people or damage property when you power up.

Step5

Start the pressure washer and test the spray. Begin by spraying away from the concrete surface and then slowly point the wand toward it from 3 to 4 feet away.

Step6

Make a few passes and then stop for a moment to see if the surface is clean. If not, move closer. Make slow, methodical passes to rinse the concrete of all dirt and other debris using water only.

Step7

After turning the pressure washer off, add a chemical for treating concrete; consult the owner's manual for help selecting the right chemical solution. If you won't be applying a chemical solution to the surface, proceed to step 11.

Step8

Add the chemical using the injector or special nozzle on the pressure washer.

Step9

Start the pressure washer and test the spray. Begin by spraying away from the concrete surface and then slowly point the wand toward it from approximately the same distance as when you rinsed it. Make slow, methodical passes to coat the concrete evenly with the chemical solution.

Step10

After waiting 5 to 10 minutes to let the solution work, pressure wash the concrete again using water to rinse away the chemical.

Step11

Allow the pathway to dry for 48 hours before sealing or coating the concrete.

Tips & Warnings

The joints or seams between slabs of concrete are vulnerable to pressure. Use care on these areas by not focusing the spray on them for too long or at a direct angle.
Use only pressure washer approved, biodegradable chemicals. Consult your owner's manual about what chemical to use on a particular surface. Non-approved chemicals can damage your pressure washer and non-biodegradable chemicals, such as bleach, will damage the environment.
Pressure washers are powerful. Never point them at people or animals; they can cause serious injury.

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Comments

ecarso said

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on 4/12/2008 Water quality concerns have not been considered other than "biodegradable cleaners." So you can use biodegradable cleaners then everything is hunky dory. NOT!!! What about whatever is being cleaned up? Is that something that should be going into our creeks, rivers, and ocean? How about mentioning a way to divert the runoff to a grass area or some other pervious surface so the junk doesn't go directly into our waterways. Or maybe using an absorbant boom to catch the nasty stuff. Or using gravel bags as a berm to catch nasty stuff that can be vacummed up after and put in the trash where it belongs.

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