Moss is harmless when growing on the ground or along a tree trunk, but this innocent green tuft can wreck your roof. In damp climates, moss on the roof may seem unavoidable. Yet, it's vital to keep the roof cleaned off and treated so moss doesn't grow, otherwise your roof may suffer the following damages.
1. Lifted Shingles
Most people think of moss as only a surface problem, but it can work its way beneath the shingles. Generally, this occurs when moss covers the edge of a shingle. Then, some of the spores work beneath the shingle and begin to grow. Eventually, the moss lifts up the shingle slightly, which then allows moisture to seep underneath. A roof leak can form anywhere that a shingle isn't laying flush on the roof.
2. Moisture Entrapment
Moisture collecting on top of the roof isn't good, especially if it doesn't dry off quickly. Moss acts like a sponge, trapping a lot of moisture on the roof's surface. This moisture then sits there, causing shingles to degrade. The shingles may even begin to rot, depending on the severity of the moss issue and how long the moisture is trapped. This increases the chances for leaks and drastically shortens the life of your roof.
3. Hidden Damage
A carpet of moss on the roof hides developing issues, so they can become quite severe before you even know that there is a problem. Moss can cover degrading shingles and even small holes. The longer a small problem goes untreated, the more likely that major water damage will affect your roof and attic. Further, while small damages can be repaired, if rot sets in, you may need to replace the shingles and the roof decking. This is much more expensive than a simple shingle replacement.
4. Clogged Gutters
Moss doesn't always stay on the roof. In heavy rain, it can become dislodged, and it will then end up in your gutters. Moss-clogged gutters cause water to backflow up onto the roof, where it can seep beneath shingles — especially those shingles that are already lifted up by moss growth. Clogged gutters also overflow, which exposes the eaves of your roof to water and can cause them to rot prematurely.
5. Weight Concerns
Remember that moss can act like a sponge, which means that it will absorb a lot of water during a rain event. Roofs are designed so that the water will run off, which means they may not be able to withstand the extra weight when moss doesn't allow the runoff to occur. This can lead to roof damage or even a roof collapse.
Contact a roofer in your area if you have a moss-covered roof so you can schedule a cleaning and inspection for damages. For more information, reach out to a local company, like The Roof Doctor.