The Art of Power Washing Siding
by Henry Bockman

Power washing siding may seem safer to take on yourself, but if you don't have the proper tools and experience it could cost far more than you intended.
    Some of the most common mistakes to avoid made by homeowners and contractors when power washing siding are:

 Trying to remove the powdery coating called oxidation on aluminum siding. Removing this coating when power washing the siding can cause discoloration and in some cases cause the siding to look like a completely different color.
Using too much pressure when power washing siding can also force water up behind the siding where it will cause mildew behind the siding or in some cases, blow the siding off the house!

Power washing the house from the top down or letting chemicals dry on the house, which may leave streaks on the siding.

Using a ladder to clean the upper areas of a house can result in serious injuries and death from slipping off the ladder.
These are the types of mishaps that many people have when attempting to do a quick power washing of their siding. If you decide to use a power washer on your home, here are some general guidelines to use.

Make sure the machine your using puts out a minimum of 4 gallons of water per minute and less than 1000 PSI.
Most homeowners will buy a power washer from a hardware store that puts out 1,000 PSI but only uses 2 gallons per minute of water.  While this machine may work, it will triple the amount of time to do the job properly.
Be careful if your making your own house washing chemicals. For example, mixing bleach and ammonia can create a poisonous gas.
We suggest that home owners buy a siding wash that's available in most hardware stores and follow the manufactures guidelines for the product. Leave the stronger agents to the pro's or you may end up removing the paint along with the dirt!
The best way to clean siding is by using a power washer that has a chemical injector built into the machine.  Using a chemical injector will allow you to pull the soap from the container, mixing it in the machine with water and spray it onto the house using low pressure starting from the bottom up. Make sure when using a power washer that you don't shoot water or chemicals up under the siding, this can cause significant mold problems behind your siding.
Allow the chemical to dwell on the siding, then using low pressure, rinse the product from the siding. Make sure when your rinsing the product off the siding that you start at one end of the siding all the way to the end. Do not stop or vary your distance from the siding, or it will cause the surface to be cleaned un-evenly.

If your siding has small black dots that do not come off during cleaning but can be scraped off using your finger nail. You probably have artillery fungus on your siding.  This can not be removed from the siding without causing damage. 

Henry Bockman
President, Henry's Housework Inc.
MHIC # 65039 Licensed, bonded and insured.
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