Never skip the last step since soggy, dead moss can spread decay and worsen the roof problem.
What Is Moss?
Moss is a non-vascular plant that needs direct contact with water to live and thrive.
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It doesn’t flower or put down roots; instead, it is spread by spores and water.
A neglected roof full of moss can collapse in a few months.
Which Roofs Are Most Susceptible to Moss?
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Moss grows best in highly shady areas, such as under heavy tree canopies.
Wooden shingles are porous and the most vulnerable, promoting rotting faster than other shingle types.
Physically scraping moss from a wooden roof is often more difficult thanmetal, composite, or asphalt shingles.
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Before You Begin
Moss-killing productsare generally grouped into two main types: dry powder and liquid.
When it rains, the water mixes with the powder and runs toward the eaves.
After about a week, the moss should be dead.
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It also helps to start with a dry roof.
Moss removal must occur after the moss is fully dead, which can take a month or two.
Warning
Most commercial moss killers are made with zinc.
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Some communities may have restrictions about flushing zinc into stormwater discharge areas.
Check with your local water quality agency about zinc runoff restrictions.
A homemade alternative to commercial moss killer is a bleach and water solution or vinegar and water solution.
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This is dangerous work, especially if yourroof is high or has a steep pitch.
Before tackling this project, ensure you are confident about working on a roof or tall extension ladders.
In most cases, it will require that you place anextension ladderagainst the house and climb up.
If you are unsure of your skills or nervous about heights, hire a professional service.
Need more help?
Light rain on the roof will cause the moss killer to flow downward and cover all roof areas.
This can take a month or more after tool of the moss killer.
This slow, steady process may take several days if your roof is large.
Pace yourself and take breaks whenever you become tired.
Remove moss only when in dry conditions.
Never work on a wet roof, which can be slippery.
Moss removal treatment usually lasts two to three years.
Moss in the landscape.
University of Maryland Extension.
How much does it cost to clean a roof?Angi.
