How to Pressure Wash a House

Misconceptions of Pressure Washing  

Most people have misconceptions of pressure washing. A commonly held view is that a pressure washer cleans with high pressure on the surface, and a higher PSI rating for a pressure washer equals more cleaning ability.

A first time user of a pressure washer will usually try to clean with pressure, if the surface doesn't come clean, then they will move closer to the surface or use a tip that produces more pressure in a attempt to clean.

Using high pressure to clean can be dangerous to both the user and the surface being cleaned.

Painted wood siding can be stripped of paint, soft wood decks can be marred and striped by high pressure, and windows can have there vapor barriers broken from the pressure.

Higher pressure is more difficult to control, and is especially dangerous from a ladder, which amateur washers will use to reach the higher areas of there home.

The bottom line however, is high pressure isn't all that effective in cleaning. Mold and other stains many times are not budged at all by pressure, but can be easily wiped off with a cloth or brush. But cleaning a home by hand with a brush or cloth is very time consuming.

High pressure cleaning is only effective on hard surfaces such as brick and concrete, even though extremely high pressure can damage the facing on brick and the finish on concrete.

The Secret to Pressure Washing

The secret to pressure washing is detergents.

Every stain on a home, mold and mildew, grease, red clay, rust etc., has a certain chemical which will break down that stain and allow a pressure washer to rinse it off.

A professional pressure washer knows what detergent will break down each stain, and how to safely apply and use the detergent. Incorrect use of these detergents can cause harm to the user, siding, and plants surrounding the home.

Moderate pressure (2500 - 3500 PSI) can be used to clean certain types of siding (vinyl, hard wood siding) but is only effective using a soap based detergent. A minority of professional pressure washers use this technique. The side being cleaned is soaped using a detergent tip. The soap is allowed to sit on the surface for a few minutes and loosen the dirt and mold. Then the siding is cleaned from top to bottom overlapping each pass with the fan spray of the pressure washer.

This isn't very difficult for lower siding, but the high parts of a home must be washed with pressure from 6"-12" away for the stains to be removed. Every square inch being of the siding must be cleaned this way. To reach the higher areas of a home, a ladder or extension wand must be used.

Professional Soft Washing 

The majority of professional pressure washers use a technique called "soft washing". Typically less than 1000 PSI is used to clean a house. Very little pressure is used, with the surface being cleaned by the detergents applied, and then rinsed by the pressure washer. By using lower pressure, there is less change of harm to the washer or the surface being cleaned.

Pros first pre-wet any plants and surfaces not being cleaned, then apply their detergent solution on the siding from the bottom up. The solution includes sodium hypochlorite and soap to allow it to cling to the surface more effectively. The solution is allowed to dwell on the surface until all the mold is killed. Any spots still left are hit with a second application of solution.

Once all the mold is gone, the professional washer rinses from the top down washes all traces of mold and debris from the siding. Then the siding is thoroughly rinsed to remove all soap from the surface, and all plants and other surfaces are throughly rinsed with low pressure.

Higher parts of siding are reached using a special tip that can shoot a low pressure stream up to 40 feet. On very high parts a 6 foot extension sometimes is used, but all the washing can be safely from the ground without using ladders.

Houses can be washed faster and more effectively than using the "pressure cleaning" technique. Pros using the "soft washing" technique generally favor pressure washers that put out more gallons per minute (GPM) and have less pressure (PSI).

In summary, smaller one-story vinyl houses can be cleaned by do-it-yourself homeowners using residential machines, however for larger two-story homes with high peaks it is best to hire a professional pressure washing company that utilizes soft washing techniques.

by HydroClean



How to Pressure Wash a House
Originally appearing at www.pressurewashinghickory.com