It’s true – this blog certainly does hammer home the concept that keeping your home’s gutters clean is essential to its long-term well-being. If you clean out your gutters two or three times each year, you will prevent debris from accumulating inside them and causing clogs; which in turn can block the flow of runoff water and lead to moisture-related issues.

But you might be wondering: how important is it to keep my home’s roof clean?

Maintain Blockage-Free Roof Valleys

In most cases, having leaves, pine needles, twigs, and other objects on your roof isn’t any cause for alarm; the biggest concern for you might be reduced curb appeal. However, it’s not uncommon for this type of debris to collect in the valleys of your roof from time to time. If left unaddressed, the valley blockages might either direct water over your gutters entirely or soak up the water to the point that the leaves never dry (which sometimes results in attic leaks).

Runoff water could be directed away from your roof valleys and gutters if they are clogged.

Therefore, you probably should get up on your roof and clean out your roof valleys if you start to notice debris piling up inside them. If you’re going to be up on your roof already to clean your gutters, it’s smart to take care of roof valleys at the same time. If you have a gas-powered leaf blower (never use an electric blower with a dangling cord that could trip you up on your roof), it may be enough to blow the debris out of your valleys. You can also use a soft broom, cleaning brush, or even your hands to do the job.

Avoid Power Washing Your Roof

An approach which is not recommended is using a power washer to spray the leaves out of your roof valleys. The fast-moving water can be strong enough to dislodge the protective granules on the surface of your shingles, which can cause them to wear out faster. In fact, most roofing companies will void any warranties they provide if a power washer is used on the shingles. 

It’s great for your driveway. But not for your roof.

Even if you notice streaks or discoloration on your roof itself, you should refrain from using a power washer. These markings are usually caused by algae growth, which tends to occur on the part of your roof that receives the least sunlight and/or takes the longest to dry after a rainstorm. The algae spores actually feed on the limestone filler inside your shingles; and although the shingles themselves aren’t harmed, the algae does produce black or green streaks on their surface – which can make your roof look ugly and unkempt.

Getting Rid of Roof Algae

The most effective way to remove algae from your roof is with a scrub brush and some old-fashioned elbow grease. Use either standard soap and water or an oxygen bleach solution as a cleaner (you can purchase roof algae cleaners, but their results vary). Avoid chlorine bleach because its runoff can harm your grass and landscaping in your yard. 

If your shingles look green rather than gray, it’s time to clean them.

It’s best to clean your roof on an overcast day to minimize evaporation of your cleaner. Divide the job into four-foot wide sections of roof from top to bottom, and never stand on a wet section of roof. Finally, you can prevent algae from coming back by fastening a three-inch wide strip of copper at the top of your roof. Since copper is a natural biocide, a little bit of the metal will be carried by raindrops down onto your shingles, where it will stay and repel algae growth.

Of course, you should always be careful whenever you are walking or crawling around on your roof. If you are concerned about your safety, call a contractor to clean your roof for you. But there’s no reason you should have to settle for a dirty or debris-strewn roof.

Written by Del Thebaud