MOST homeowners realize the value of interior cleaning, but they often fail to appreciate how important it is to clean the exterior of the house. It is, after all, the first thing your visitors see. More important, a good washing will remove the dirt and grit particles that collect during the year. When agitated by the wind and rain, these abrasive particles can quickly mar or damage your siding or masonry. An annual cleaning can help prolong the life of those surfaces.
It might seem that washing an entire house is a Herculean task, but it’s not especially difficult. There are a number of tools, techniques and cleaning agents that can make the job easier. But careful planning and preparation are essential if you want to do the job right.
It is best to wait for a warm, dry day. Do not try to wash on a windy day or you will be fighting overspray. First, protect the area around the house. Cover small plants, shrubs and areas of lawn near the house with plastic sheeting. Move lawn furniture and other movable objects away from the house. Use duct tape and plastic sheeting to cover all vents, electrical outlets and outside light fixtures.
Next, inspect the house carefully.Look for areas with heavy stains (rust, organic or mildew stains or heavy deposits of grime) or efflorescence (white powdery deposits of crystallized salts) on masonry surfaces. These should be cleaned by hand first, or the stain may run onto adjacent surfaces when washed.
In most cases these stains can be removed with soap, water and a scrub brush. Stubborn stains may require a stronger cleaning agent. Rust, for example, can be removed with a solution of oxalic acid (one-quarter pound of oxalic acid powder per gallon of water). After washing off the stain, neutralize the residue acid by washing the area with a sodium bicarbonate solution (one-eighth cup of sodium bicarbonate per gallon of water). Take the time to repair the rusted metal now (rust treatment was covered in the Home Clinic of April 30, 1995) or the stain will reappear.
Use a solution of ammonium sulfamate powder, an herbicide, (one ounce of powder to a gallon of water) to remove organic stains. Neutralize the area with a sodium bicarbonate solution. Mildew can be removed with a solution of oxygen bleach powder (one-quarter pound and one-eighth cup of dishwashing liquid per gallon of water). Rinse the area with clear water.
You can scrub efflorescence off masonry with a solution of phosphoric acid (one part phosphoric acid to nine parts water. Remember to add the acid to the water and not the water to the acid). Neutralize the area with the sodium bicarbonate solution.
Oxalic or phosphoric acids are available at janitorial or chemical supply centers. Ammonium sulfamate is available at most garden supply centers. Sodium bicarbonate, baking soda, is available at supermarkets. These are strong cleaning agents, so test them in an inconspicuous spot and avoid using them in concentrated strengths. Wear protective goggles and gloves.
Once you have cleaned the trouble spots, you can turn your attention to the rest of the house. If the exterior surfaces are heavily soiled, consider renting a pressure washer to clean the house; otherwise you can do the job with an ordinary garden hose and an automobile brush (available at auto supply stores). The brush has a threaded coupling that allows you to screw it onto the end of the hose. For reaching overhead sections you can attach extension poles.
Most brush units have reservoirs for cleaning agents, but first try scrubbing the walls with plain water. If that does not remove the dirt, then add the detergent. Keep in mind that excessive amounts of any cleaning agent can affect the plants and vegetation around your home.
Before starting, make sure that all doors and windows are closed. Turn the water on, then start at the top and work down to the bottom of the wall. Work in overlapping sections about five feet wide. If you have used a cleaning agent then go over the wall again with clear water to rinse the detergent away.
The pressure washer generally comes with three nozzle attachments, of 15, 25 or 40 degrees, for shaping the width of the spray pattern. The 15-degree nozzle is the most useful because it produces the narrowest and most controlled spray.
Pressure washers also have a reservoir for cleaning agents but in most cases power spraying with clear water will be enough. For high walls you can attach an extension wand to the pressure hose. Be careful, however, when you use this extension around electrical lines. Accidental contact with a high-tension line can be fatal.
Pressure washers are not difficult to use, but they can cause damage if not handled properly. Have the rental dealer demonstrate the unit. High-pressure water can actually penetrate the skin and cause severe injury; never put your hands near the nozzle or point the spray wand at people or animals. Be sure to wear safety goggles.
When washing lap siding, angle the spray down to keep the water from penetrating under the siding. Do not spray directly at windows; the water pressure could break them.