Pressure Washing

Proper Preparation Prior to Painting Prevents Poor Paint Performance! 

Its easy to prepare a the exterior of a house for painting! All it takes is a bucket of water, a scrub brush or sponge, some TSP type cleaner, perhaps a little bleach, a bucket or garden hose for clean water and lots of elbow grease.  If the surface area is really large, has lots of chalky paint, is peeling or heavily stained, then TSP and elbow grease may not be sufficient.  That's where pressure washing comes into play.
What is pressure washing?
In its most simplest term, pressure washing uses a relatively low amount of water at high pressure to give the water more cleaning power.  Household water, from a sink or garden hose, is typically under 40 pounds per square inch (PSI) of pressure.  Commercial gas engine driven pressure washers are typically in the range of 1,500 - 4,000 PSI.

In what instances would pressure washing be recommended?
In addition to removing dirt, grime, loose paint, chalking or peeling paint, pressure washing is great for cleaning roofs, fences, sidewalks and pool areas.  It can also be used to clean equipment and vehicles, engine compartments, undercarriages, heavy equipment, boats, decks, mobile homes, kennels, service bays, trash dumpsters and hundreds of other uses.

Is pressure washing by itself sufficient?
In the majority of instances the answer is yes.  There may be times when chemical cleaners might be added via an injection port on the equipment.  Sometimes abrasives are added.  And, sometimes hot water with chemical injection might be appropriate.

What operating pressure is best?
That depends.  Typically 1,500 PSI will do the trick.  However, there will be instances where 2,000 PSI might be more appropriate.  Beyond 2,500 PSI the amount of dirt, grime or loose paint removed doesn't increase.  However, the speed of removal does increase.  ALLPRO offers a complete line of pressure washers.  The most popular units are 3,000 PSI gas engine units with belt drive.  We also offer several direct drive units ranging from 1,500 - 3,000 PSI.

How important is flow rate or gallons per minute delivered?
Delivery is almost as important as pressure.  Pressure will dislodge loose particles and contaminants while the flow rate or water volume moves the particles from the surface.
Are there different nozzles or tips to help make the job easier?
Just like different tip sizes for airless sprayers, there are different nozzles for pressure washing.  The narrower the angle, the more concentrated the pressure.  The zero degree nozzle is often called the "Blaster".  It provides a concentrated spot of high pressure water.  Care must be exercised with this nozzle as the force may actually penetrate soft materials or surfaces.

What other nozzles are available?
The 15 degree "Stripper" nozzle provides a narrow fan of concentrated water for removing paint, mildew, chalk, etc.  The 25 degree "Cleaner" provides a wider fan for pressure cleaning and oxidation removal.  The 40 degree "Rinser" provides a wide pattern spray that is best suited for the removal of dirt, rinsing and sweeping to remove residue.

How close should the nozzle be held to the work surface?
The most effective cleaning range is within 12 inches of the surface.

What is the right working angle for cleaning?
Actually, its found through trial and error.  Its best to try several different angles between the spray and the surface being worked.  The best angle will be quickly identified.  By the way, the angle will usually vary from area to area and will vary from one surface to another.
Are there some simple rules to remember about nozzle selection and closeness to the surface?
Absolutely!  The narrower the fan and/or the closer the nozzle tip to the surface being worked, the more intense the pressure.  Use caution around windows and surfaces that might be damaged by too concentrated a spray or excessive pressure.