Moss: A Quiet Threat to Your Roof

Moss: A Quiet Threat to Your Roof

Moss is fine in the forest but, if you have the fuzzy plant growing on your roof, it is far more than just unsightly. In addition to giving your roof an unattractive, blotchy appearance, a moss infestation on your roof can leave you with water damage to your home and a large bill from the roofer.


Moss causes damage to roofing materials in a few ways. First, it holds water against your roof’s surface, which can cause rotting.

Water trapped by moss can also crack and pull apart your roof’s shingles as it freezes and thaws. The moss can even damage your roof directly– it prefers to grow near the edges of shingles, which puts it in the perfect position to pry the shingles apart as it grows and expands.

Moss also has root-like structures called rhizoids that burrow into and under your shingles and cause pitting. Roofing experts recommend that you take steps to control moss as soon as you see discoloration on your roof. For a deeper look at caring for your roof, take a glance at our Roof Cleaning 101 – The Complete Guide.


A roof inspector can tell you what is causing any discoloration you see on your roof. In general, algae forms a slippery green or black coating on surfaces, moss is velvety and green, and lichen is scaly and comes in a variety of colors.

Power washing is a risky proposition for removing moss. It can cause damage to shingles as it tears the moss free, or the force of the water can rip shingles off.

Bleach will kill the surface moss, but bleach runoff will also kill the plants around your house. Bleach can accelerate corrosion in your roof, gutters and downspouts.

Steve R. told us how he relies on Wet & Forget Outdoor to keep his roof free of damaging moss and other stains:

“We have been using Wet & Forget for about 6 years. Living in SW Florida our tile roofs start to get moldy and dirty after about a year and a half. Many have hired someone to pressure wash their roofs at a cost of at least $300. Our roof looks better than most that have had their roof pressure washed a year ago. We apply Wet & Forget each spring just before the rainy season starts. I do not have to walk on our roof because the pump I use will reach our entire roof from a step ladder. Many know that walking on a tile roof may cause the tiles to crack and break. Fixing broken tiles can be expensive. I have recommended Wet & Forget to many others and they are extremely satisfied with the results. It is well worth the cost of this product. Just make sure you follow the directions exactly or it will not work as it should.”

We’re happy to hear it, Steve!

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