A pressure washer is one of those tools you don't really need until you really need it. It's the only way to manage the large amounts of mud that find their way off the site and onto your customers' driveways, sidewalks, and street. It's great for a range of other tasks, too, so it doesn't just take up space in your shop. More good news: According to manufacturers, you don't need a behemoth machine to effectively tackle cleaning duties all over the jobsite.
What You Need It For
You may like those days when the jobsite is muddy–but you can bet your customers don't. If their driveway is nice light-gray concrete, expensive pavers, or smooth black asphalt, you can be sure they want it that way after you're gone. But clay, slurry from cutting concrete, muddy tires, and the oil slick from your painter's jalopy are all likely to fuse with that surface and create a challenge you need to deal with before the final check is written. And a garden hose just won't get the job done.
You also can pressure-wash equipment: You can't take a skid-steer to the car wash and pressure washers work better than a garden hose on a fleet of service vehicles. Pressure washers also are winners for paint prep, whether it's wood siding or a concrete slab, for cleaning moldy vinyl siding, and for maintaining wood decks.
What You Need
Recommendations vary from 2,000 to 2,800 psi, but a safe bet for powerful jobsite service is to get a unit with 2,600 psi and a flow rate of 2.4–2.5 gallons per minute with a 5- to 7-hp gasoline engine. A unit of this size will not only provide power but also the portability you need to get from site to site. And, when it's not cleaning, it won't take up more than its fair share of shop space. A good rule of thumb is to buy as high a psi and gpm spec as you can afford within the pressure range above and consider the size of the unit and how often it will be used. Anything more than 2,800 psi on the jobsite is generally considered overkill.
For serious, frequent use, check the pump. Some pressure washers like the Excell XR2600 come with maintenance-free pumps while other pumps require occasional oil changes. If you really plan to put the unit into service, buy one with solid ceramic pistons, brass heads, and brass quick-connects. For occasional use, plastic quick-connects or twist-on connections work, but not as well.
Use it Carefully
Adjusted to the wrong fan setting or with the wrong tip installed, pressure washers can tear wood fiber apart (you can practically drill a hole through a deck board). And if you pass it unevenly and carelessly across a surface, you can easily leave streaks, particularly on concrete. To avoid this, use the right tip or setting for your application, be conscientious about bringing the wand gently onto and off of the work, and use an accessory called a Power Broom, which maintains a consistent distance between the wand head and the work.
Detergents are sold for use with these machines, but applying them with the machine at a billion miles per hour can be overkill. It's often better to mix and apply them yourself with a garden sprayer, say for a deck cleaning, says Dan Sanchez at Maxus. You have more control of where the detergent goes and the more gentle application gets more detergent on the material and you have better control of how much it's diluted.
Freezing temperatures are bad for pressure washers. Follow all manufacturer recommendations for emptying water from the system, or you'll pull it out of the shed in the spring to find a part or fitting cracked by ice. Use a fluid product called Pump Saver for storage in freezing temperatures. Also, use a gasoline stabilizer.
So if that dirt pile turns into a mud disaster, save yourself a guess at the supply house: Consider how much you'll use the tool after this mess, then buy as much psi and gpm as you can afford to get the maximum tool for the dollar.