The roof of your house is probably the one part that receives the most exposure to the elements. Over time, mold, mildew, moss and discoloration can occur if you don't maintain a clean roof. This can cause significant damage to the shingles or tiles, creating costly repairs. You can prevent these unnecessary costs by keeping your roof clean. In addition, a clean roof can add value to your house, in the event you want to sell it.

Many people and professionals use a power washer to clean roofs however, this doesn't get rid of all the stubborn mold and mildew and doesn't prevent them from returning. If you do choose to use a pressure washer, it is highly recommended that you follow it up with the following method. This will ensure that the mold and mildew will not return for some time, if at all.

In a plastic bucket filled with hot water, pour a cup of plain chlorine bleach and a cup of powdered laundry detergent. If you don't have powdered detergent, you can also use liquid. Generally, a capful of liquid detergent will equal a cup of powdered, but check the label to be sure. Always wear gloves when cleaning. Although none of the ingredients are particularly toxic, they can be abrasive when left on the skin. Safety goggle are also a good idea, and always make sure you wear shoes that have a good tread, for grip on the surface of the roof.

Pour the cleaning solution into a garden sprayer or similar device. Spray the roofing evenly and generously, being sure to get the solution into the grooves and between shingles. If the weather is dry and sunny, spray small, manageable portions of the roof at a time, so that the solution doesn't dry up on the surface. Let the solution sit on the roof for at least fifteen minutes, to allow it to kill mold and mildew.

Use a long-handles brush with hard bristles and scrub the area. Rinse the area with water to check your progress and reapply the solution if the area isn't fully cleaned. Always allow each area to dry before moving to a new one, as it can be dangerous for you to step in a wet area. A good rule of thumb is to clean the lower areas first, then move upward.

Once you have cleaned the entire roof, give it a second rinse, to remove any leftover debris. Its also a good idea to clean out your gutters at the same time, as they too can be a breeding ground for mold and mildew.