How to recognise when roof moss becomes dangerous

Roof moss is practically unavoidable in a rain forest climate like ours here on the west coast, with near constant moisture for over 80% of the year. So, most roofs have some moss on them. But at some point it goes beyond just being unsightly and starts becoming a real danger to your roof–and wallet. It starts with shingle degradation and can end with having to replace your roof! To avoid this scenario, your best bet is to keep roof moss manageable by taking care of it periodically. Here are some danger signs to watch for so you can see when it’s time for roof demossing.

Signs it’s roof demossing time

• A build-up of moss
• Curling/cracked shingles
• Losing shingle granules
• Sagging roof

The problem with roof moss is it holds moisture. So the area underneath the moss is always wet. Shingles are not designed to be always wet, so they start to degrade under those conditions.

The first sign your roof needs demossing is when you can see a build up of moss. Moss has a way of growing between and under the edges of shingles, as you can see in the picture. When the air temperature drops to freezing, the water in the moss expands and lifts the shingle, allowing it to work even deeper. This freeze/thaw cycle breaks the weather-tight seal keeping water out, so your roof starts developing leaks.

Damaged shingles are also a sign it’s time to remove the moss. Look for curling or cracking shingles, or shingle granules constantly washing down into your eavestroughing. Shingle damage caused by moss is cumulative so this is a clear sign demossing is past due.

Lastly, if your roof exhibits signs of softness when pressed, or sagging, there’s a good chance rot has already settled in under the moss. Roof demossing is critical at this stage, not just to save as much roof as you can but to prevent further loss and even injury to occupants should the underlying structure become too weak to support itself anymore.

Demossing is something you can try doing yourself, but it’s not advised. It’s difficult, time-consuming, requires special equipment, and is, frankly, dangerous. The recommended route is to hire softwash professionals. Softwashing is an affordable option that comes with several additional advantages. For example, softwashing uses biodegradable, environmentally friendly solutions that are non-toxic and safe for people, pets and plants. It also uses soft-bristle brushes to gently remove the moss without harming shingles. Notably, moss is guaranteed not to return for years.

Time to demoss your roof? Contact award-winning 2 Angels Home Service to book an appointment. 604-825-1712