Moss can dramatically shorten the life of your roof. Moss has excellent moisture retention like a sponge, meaning it is constantly damp from rain and slow to dry out. This moisture promotes rot in wood shakes. It causes composition or asphalt shingles to lift which allows water to get underneath the shingles to the decking causing rot. Moss also causes the composition roof to shed its UV- & fire-protective granules. It leads to softening in tile roofs. When the moisture in the moss expands and contracts with temperature changes it can cause cracks and split tiles. Once the tiles crack and split, more moisture is allowed to seep underneath the tiles and damage the wood decking and other structural materials underneath. Metal roofs may seem impervious to moss damage, however, they are not. Moss, algae, lichen, and other such growths block moisture’s release, resulting in standing water. The feeding action from moss and algae growth can actually cause significant damage to a metal roof. Moss holds onto water trapping it against the metal roofing. As we all know, water corrodes metal, and over time this damage can become more and more serious. The water and digestive material in the moss can also discolor and stain the roof, making it unsightly once the moss and algae are eventually cleaned off.
Moss is also a fire hazard since dry moss in summer can provide tinder for sparks from a chimney, wildfire, or even Fourth of July fireworks.
Consider professional moss removal
Call a professional roof maintenance company if the moss on your roof is thick or widespread. They can determine if a commercial treatment can get rid of the moss or, if not, discuss alternatives.
While traditional pressure washing, which you may have used years ago, is effective for ridding roofs of heavy moss growth, it can damage the roof if the water pressure is too high. Many experts, including the Asphalt Roofing Manufacturers Association, recommend a gentler hybrid approach, sometimes called a “soft wash.” It uses low-pressure water assisted by a biodegradable cleaning solution formulated for roofs.
Even if the moss on your roof isn’t too bad, you’ll want to hire a professional if you’re unsure you can safely climb the ladder yourself. Your roof is a dangerous place – it’s high, steep, and often slick. Professionals have the products, expertise, and gear to handle the job with less risk.
DIY moss removal for wood shake and composite roofs
If you’re confident that you can safely remove the moss on your own, these tips can help you get the best result:
- Avoid walking on fragile roofs. If you see cupped or curled shingles, stay off them. You could crack the shingles, and they’ll need to be replaced.
- Manually remove as much moss as you can. You may be able to dislodge some of it with a broom, particularly if the roof and moss are thoroughly dry. Always sweep downward, toward the gutter, to avoid lifting the shingles.
- Consider a commercial moss treatment. They’re formulated to be safe for your roof and non-corrosive to gutters. Before visiting the hardware store, know the approximate square footage of your roof so you buy the right amount. Also, carefully follow the manufacturer’s instructions to minimize runoff that could damage your landscaping or harm local waterways. If possible, look for environmentally friendly formulations, and always wear protective clothing (gloves, long pants, sleeves, and safety goggles) when applying a moss treatment.
- Think twice about home remedies. A quick online search offers plenty of home remedies for removing moss – and not all of them are good. Avoid using laundry detergent as a moss killer. The degreasers in detergent are too strong and can attack and break down the water-shedding properties of some roofs. Roofs can start leaking within days of being treated with laundry soap. Use caution if installing zinc or copper strips to discourage future moss growth. While they may be effective for a while, the Asphalt Roofing Manufacturers Association says they can cause leaks during installation and don’t recommend them. Vinegar is a safer home-remedy alternative. During a stretch of dry weather (so it won’t immediately wash off), pour straight vinegar on the mossy sections of your roof. In a few days, the moss will turn brown and die, and you can use a broom to sweep it off. Vinegar also kills moss on patios and in cracks in the driveway, and it’s nontoxic for pets that might walk across it.
Clean gutters to prevent damage
Clogged gutters can overflow during spring storms, flooding your basement or crawlspace, damaging siding and fascia boards, eroding planting areas, and even impacting your foundation.
Consider hiring professional gutter cleaners because of the safety risks of climbing ladders. If you do clean the gutters yourself, follow these tips:
- Don’t lean your ladder against gutters or downspouts. Keep your body inside ladder rails with one hand always on the ladder. Never hold a gutter or downspout for support and, to avoid slipping, don’t clean gutters in the rain.
- Scoop out debris rather than using a leaf blower. Leaf blowers are unwieldy and can throw you off balance atop the ladder.
- Stuff a cloth in the top of downspouts to prevent debris from washing down if you use a hose. Remove the cloth when you’re finished and watch to make sure the water drains. If it doesn’t then…
- Use gentle water pressure if the downspout is clogged. Downspouts can’t take the same kind of pressure as other pipes. You also can try using a plumber’s snake or disconnecting the elbow, if that’s where the clog is. If your downspout drains to an underground pipe and dries well, then it is better to disconnect the elbow before cleaning to keep out debris that could block the pipe and require you to dig it up.