Encyclopedia

of Home Improvements

*Power Washing*

There are a couple of basic elements to the power washing process. The high-pressure flow of water that the power washer produces breaks the bond between the dirt and the surface that you are cleaning. Detergents are useful to help emulsify dirt and oil stains from surfaces such as concrete.


Unfortunately, pressure washers are not created equal. The cheaper washers usually do not have enough power to do the adequate power washing. I use a 2800 psi gasoline powered pressure washer that has always done a good job for me.

There are different nozzles that will adjust the spray of the washer. I have a 0 degree nozzle that works well to get to high places but will damage a deck! A 15 or 25 degree tip is good for most cleaning projects. When using different nozzles it is important to test an area first to make sure that you are using the proper tip at the right distance to the surface being cleaned.

Power washers are a wonderful machine to have when you use it properly. It can save a lot of time and energy but can also be very dangerous when not. Always where proper protection and never ever aim it at another person.

Power washing a Deck

I don't recommend that you use deck cleaners. Most cleaners have bleach as their brightening. Using a product with this ingredient on your deck can be a problem. If you do decide to use it, you will soon learn how hard the bleach is on the wood. The liquid will certainly take away the gray and will kill the mold spores, but at the same time it will mangle the wood fibers and leave a residue, which will keep stains and sealers from penetrating the wood properly. (

Since a deck is a horizontal surface, it is at the mercy of the elements. The sun breaks down the surface fibers, causing the wood to weaken and turn gray during the process. Rain and snow soak the surface causing the wood to swell excessively, and eventually leading to the breakdown of the internal fibers. Once this happens, the wood becomes spongy and weak. Bird droppings, smog and people walking over it complicate the problem even more.

There is a definite technique for pressure washing decks. If not done correctly, you can damage or scar wood. The best and easiest way to learn deck wash technique is to practice on old boards. The wand should always be kept in motion when it is close to the wood. Stopping the wand while still spraying water will scar the wood. To avoid scaring, arc the wand up and away from the surface at the end of each stroke.

It is imperative that you now rinse your deck thoroughly to get rid of all the crud you created with the cleaning. Look close. You will see what I mean. Using your hose or power washer (white tip if using power washer) thoroughly rinse the deck, rails, rail cap and steps. Be sure you get in the tight spots. It's best to rinse the outside of the rails, then the inside of the rails, then the deck floor and finally the steps. When that is done, rinse the outside of the deck frame and finally the posts. It's important to do this in this order. It does you no good to clean the deck floor and then the outside of the spindles which will blow the crud back on to the deck floor.

Power washing a house

Power washing houses should also be done when you want to prepare it for new paint by removing a chalking residue from old oil or latex paint. High-velocity power washers are exceptionally good not only because they're fast but also because they scour the old paint so the new coat will adhere better.

Pressure washing will work on wood, granite, asphalt, bricks, aluminum and vinyl. It is important to try a small area of the house to make sure that you have the correct nozzle and water pressure to do the job. A 15 or 20-degree nozzle should work well on most areas of your home. On cedar siding you may want to use a wider nozzle so as to not damage the cedar, which is a soft wood.

Be very careful when using a power washer while working from a ladder because the recoil from the pressure can knock you off balance. Make sure you cover all electric outlets and always avoid lights since water can create a short circuit.

Before you pressure wash black spots and clean top corners, identify whether you are dealing with fungus or just extremely dirty areas. Spray any household bleach on the blackened area and if it does not fade away you can clean it with a pressure washer. If it does, you will have to use a brush.

In order to protect your face and eyes, wear goggles and also wear clothing that will keep you from getting soaked. Even though you are wearing protective gear during house pressure washing, you can expect to get wet.

Be extremely cautious around windows and outside lights because they can break in seconds. If you are pressure washing a wood surface, do not hold the spray gun directed at one point for extended periods. If you do, you will make a dent and damage the wood. Remember to move the nozzle constantly and at a steady pace. On the other hand, if you are working on paint removal in order to prepare the surface for a fresh coat of paint, the gauging will be inevitable. When pressure washing the walls, choose your own pace. Determine how dirty the surface is and based on that decide how fast or slow you need to move in order to clean the walls. Remember to close all the windows! When spraying around windows, please hold the wand at an angle so that it does not reach joints, gaps or the glass. Do not forget to remove all shutters and wash the area underneath, since most of the time it is the place where you will find spider and wasp nests.

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