What Causes Moss to Grow on Roofs? (Demystified)

If you want to prevent moss from growing on your roof, start by hose-off your roof. Then, scrub the moss with a soft-bristled brush to remove it. You can also buy a ready-made cleaner that comes in spray bottles that attach to your hose and let it sit according to the label’s instructions.

Debris on Your Roof

Moss thrives on the organic matter that makes up your roof, including branches, leaves and twigs, and even dead animals. These materials can pile up on your roof and provide the shade and moisture that moss needs to grow. This debris can also block the flow of water from your roof, which will eventually cause damage to your shingles and lead to leaks in your home.

Mosses are also very absorbent, soaking up the rain that falls on them and retaining it for long periods of time. This can degrade shingles and allow water to seep through your roof, leading to rot and mold. It can also pull up and loosen shingle edges, which can lift the edge of your roof, allowing more water to get in.

It is important to regularly clean your roof and remove any organic material that builds up, to keep it free of moss and other unwanted growths. This is especially important in areas where trees are overhanging, as these branches can provide the necessary shade and moisture for moss to thrive.

When removing moss, you can use a variety of tools, including long-handled brushes and scrapers. Always be careful when working on the roof, as it can be slippery and unsafe. If you are not comfortable removing moss from your roof, contact a professional.

Even though it may look dead, moss can stay alive for months without any sunlight or water. Once it gets exposed to water again, it can start growing rapidly.

While regular cleaning can help manage a moss problem, preventing it is much easier and less costly in the long run. There are a number of options for preventing moss on your roof, including sprays and coatings that prevent it from growing. Changing to a metal roof that is not friendly to moss can also be an option for some homeowners.

While a little bit of moss may seem harmless, it can quickly turn into a major problem that requires extensive repairs or even replacement of your roof. If you have any moss on your roof, it is important to address it immediately and take steps to prevent its spread.

Tree Branches Overhanging Your Roof

Moss thrives in shady, damp areas. If you have a lot of tree branches overhanging your roof, they may promote its growth. As the moss grows, it creates a heavy layer that adds weight to the roof. This can rob the shingles of their strength, shortening their life. It also traps moisture, which can lead to rot and mold.

As a non-vascular plant, moss doesn’t use roots to absorb water. Instead, it sends out spores that become airborne and can land on your roof. When they do, the spores will find damp spots and start to grow.

The abrasive nature of tree branches rubbing against the shingles of your roof can cause subtle but relentless damage over time. This damages the protective layer that keeps shingles intact, which makes them more susceptible to rot and leaks.

Overhanging branches can also block sunlight, causing dark areas that promote the growth of moss and algae. If these stains aren’t removed, they can affect your home’s curb appeal and reduce its value.

If you spot moss growing on your roof, it’s important to take action immediately. Moss sucks up water, which can ruin the shingles. The moss then spreads beneath the shingles, where it eats away at the wood and can eventually lead to rot. If left untreated, rotting shingles can allow water to seep into the roof framing and into your home, causing significant damage that requires expensive repairs.

You can clean moss from your roof by hosing it down with a hose and a scrub brush. Be sure to wear proper clothing and safety equipment, including rubber gloves, a hard hat, eye protection, and a sturdy ladder. Before you begin, cover nearby plants with plastic sheeting and put a safety rope or harness in place on the ladder. When you reach the top of your roof, hose off all the moss-covered areas to make sure none of it is lifting up the shingles. You can then scrub the moss with the brush, working in one small section at a time to avoid lifting shingles.


Moss grows well on a roof because it thrives on moisture and shade. Shade keeps the roof cool and damp. It also prevents the evaporation of water, which provides the necessary moisture for moss to grow. If a tree leaves large branches or debris on your roof, it can cause water to build up and create the perfect conditions for moss to start growing.

As moss grows, it clings to and spreads across your roof shingles. This can cause them to loosen, which leads to leaks. It can also cause other problems like damaging the structure of your roof.

If a moss problem develops on your roof, it is important to remove it as quickly as possible. This will help to ensure that the moss does not grow deeper into your home and cause more damage. A professional roofer will be able to assess the extent of the moss and determine the best course of action.

To keep moss off your roof, trim trees so that sunlight can reach the surface of the roof throughout the day. Regularly clean your gutters to remove leaves and other debris that may have landed on the roof.

A metal roof is the most moss-resistant roofing material available. Moss tends to grow on dark surfaces that don’t receive much sunlight, so a metal roof is an excellent choice for homeowners who want to avoid a moss problem.


Moss grows as a non-vascular plant, meaning that it does not send out roots into the ground like most plants. Instead, moss spreads through the air via its spores, one-celled reproductive units that are carried by wind and rain. The spores can land on your roof, where they grow in the damp and shaded environment. Moss is also an excellent absorber, soaking up rainwater as if it were a sponge.

The longer moss is able to live on your roof, the more damage it does to your shingles. Moss creates a damp surface where water collects, which shortens the lifespan of your shingles and causes leaks. Moss also blocks sunlight, which causes a roof to become hotter, leading to premature shingle wear.

Professional roofers like these Buffalo roofers can diagnose and treat a moss infestation. If the infestation is severe, it may be necessary to replace a number of shingles and address other roofing issues as well. A professional can also advise you about preventive measures that can reduce the likelihood of a moss outbreak in the future.

Preventive measures include removing debris that accumulates on the roof, trimming tree branches and keeping gutters clear of debris. The roof should be inspected and cleaned at least once a year to ensure that water is draining properly. It is also a good idea to switch to a more hospitable roof, such as a metal roof, to discourage moss and other growths from growing on it.

If you are tackling a minor moss problem on your own, it is best to do the work during a cloudy day when moisture is less likely to evaporate too quickly. Place a ladder near the area of the roof where you are working and secure yourself with a safety rope and a pair of rubber gloves. Start by hosing off the mossy areas with a garden hose set on a low pressure setting. Then, scrub the moss with a soft-bristled brush. After scrubbing, use a cleaning solution such as Zinc Sulfate (monohydrate). Follow the manufacturer’s instructions for application.