The consistent color and orderly texture of a new roof makes even the humblest house a castle. In a few years, though, stains can mar the fresh appearance of a roof that still has many years of usefulness ahead of it. Steep or complicated roof lines can make cleaning the roof too hazardous for the do-it-yourselfer. If your roof pitch is shallow enough that you can walk on it, however, consider washing it with materials you may already have at hand. Learning to clean Owens Corning fiberglass shingles serves as a primer for cleaning many brands of 3-tab roofing shingles.
Fill a pump sprayer with one-half water and one-half chlorine bleach solution, then secure the lid firmly.
Wet down plants beneath the roof thoroughly to minimize the damage that splashing bleach solution can do to them. Alternatively, cover them with plastic tarp.
Access the roof by stepping through a dormer window or by climbing a sturdy extension ladder. The bottom of the ladder should extend from the house at least one-quarter the distance from where it rests on the roof or the gutter. Push the ladder's flat feet firmly into the soil or rest it on even paving. Place the ladder as close to the middle of the roof as possible.
Sweep dirt, twigs and leaves from the roof with a broom. A wide corn broom is large and flexible enough to make quick, gentle work of this task. Don't use a rake, which can remove the mineral granules that protect the shingles from damage. This is also an excellent time to remove debris from your gutter.
Pressurize the pump sprayer by engaging the plunger several times. Set the nozzle to a coarse, wide spray. Coarse sprays are easier to control and help prevent the spray being inhaled by the user. Pointing the nozzle at the roof, squeeze the trigger to test the spray. Adjust the spray if necessary.
Wet a 3-by-3-foot or 4-by-4-foot swath of roof with the solution. Start at one end of the roof, at the top.
Scrub the area with a soft car washing brush. Adjust the telescoping handle to a comfortable length.
Move down the roof to the next section. Working from top to bottom prevents your stepping on a wet, slippery roof. Continue working down the roof until you reach the bottom, then climb back up and start on the next vertical section until you reach the middle of the roof.
Proceed to the opposite end of the roof and do the same, moving from top to bottom toward the center of the roof. By the time you reach the final vertical section in the middle, the last section you did on the opposite end should be dry enough to walk on. If not, descend the ladder and wait an hour or so for the roof to dry before doing the last section. If you have to wait, give the plants under the roof a good soak to wash away splashed bleach.
Hose down the roof with water after cleaning the last section to rinse away any remaining bleach. Give the foundation plants their last rinsing with the hose.