Moss Removal From a Metal Roof

May 12, 2022

Can Moss Grow on Metal Roofs?

Moss spores are carried by the wind, or even birds, and can land anywhere, including your metal roof. Moss attaches itself to any organic material that is available, and uses this as its anchor, or base, for growing. Often on a metal roof, the organic material that moss attaches to is pollen from nearby trees, decomposing leaves, or even bird droppings. Amazingly, you can see this happening on metal that seems to have no dirt on it.  Notice old cars sitting in the shade, and how stained they are. Yes, even metal roofs are susceptible to these growths which can quickly make them look drab and tarnished.

Can Moss Damage a Metal Roof?

Metal roofing is strong and durable, providing many benefits when compared to other roofing options. However, even with how strong and durable it is, the surface can still be damaged from moss or algae growing on it.

Moss may seem harmless, but the feeding action from it can actually cause significant damage to a metal roof. Moss has excellent moisture retention, meaning it is constantly damp from rain and slow to dry out. This water is then trapped against the metal roofing. As we all know, water corrodes metal, and over time this damage can become more serious. The water and digestive material can also discolor and stain the roof, making it unsightly once the moss and algae are eventually cleaned off.

Fortunately, there are some ways to prevent these from growing as part of regular roof maintenance.

How do you remove moss from a metal roof?

DIY Metal Roof Cleaning solution

Mix: 1/4 cup detergent (5% detergent solution) which can include car washing soap or mild dish soap per gallon of water. Do not use a laundry detergent.
Apply the solution to the surface using a sponge, microfiber cloth, or soft-bristle brush.
Let stand for 5 to 10 minutes.
Thoroughly rinse the surface with plain water.

DIY Vinegar Metal Roof Moss Killing Solution

Another excellent way to clean metal is by using vinegar in your solution. A natural disinfectant, it is strong enough to eliminate most bacteria and help remove the build-up of mildew, as well.

Add 1 gallon of warm water to a bucket.
Add in 1 tablespoon of vinegar and 1 pound of salt
Add as much mild soap as you want, as long as it doesn’t make up more than 20 percent of the total mixture.
Mix well. Spray the solution and wait 5 minutes then wipe with a microfiber cloth and thoroughly rinse.

Can I pressure wash a metal roof?

Most metal roofing can handle gentle cleansers and soft pressure washing without causing any damage to the surface of the roof or the structure.

Can I walk on a metal roof?

Metal roofs are made with different materials such as steel, aluminum, or alloys/ combination of the two. And even though metals can be galvanized, they won’t be as strong as cemented roofs or brick. Most metal roofs can stand up to you walking on them better than ceramic tiles and some other roofing systems. However, several factors come into play to avoid damaging your roof. To safely walk on your roof, you need to understand the roof type, have the right shoes, use roof-top support equipment, and ensure the conditions are right. What’s more, some roofing industries have other prerequisites for these roofs such as don’t exert force on certain spots of the roof.

Understanding the Type of Metal Roofing

First and foremost, you need an understanding of the type of metal roofing used. What does this mean? Well, there are four types of roofing styles most manufacturers use. They are;

  • Standing seam roofing
  • Metal tile roofing
  • Corrugated panels
  • Metal shingles

For all these metal roofing styles, you should walk strategically to avoid falls, accidents, or damage to the roof.

Standing Seam Roofing

This is the safest metal roof to walk on since it holds up weight pretty well; you can literally walk all over it, at any spot and you won’t damage it. However, the type of shoes worn matters.

Metal Tiles

These ones are made to resemble any other tiling solutions such as ceramics or shake.

They are a bit fragile hence, you should walk on lower spots in the flat area of the panel and near the roof panel supports (roof deck).

Corrugated Panels

Since they too are screwed on the roof decking, the roof decking should be the safest place to walk over.

Metal Shingles

Simply walk on the upper part of the shingle panel,  there’s where the strength is highest and with minimal airspace in between the metal. However, metal shingles can get easily damaged if you don’t walk in the right spots. This is why there is an option of installing foam backers.

If you are concerned that you will need to have foot traffic on the roof have foam inserts or backers installed. Their purpose is to seal any air gaps left open on the metal panels, shakes, or tiles, as they can increase the chances of bending or damaging the roof altogether.

Polystyrene foam backers offer additional support, rigidity, and steady walkability on the roof.

Tips to Walk Safely

Metal roofs are not all that safe to walk on, however, this doesn’t mean they are impossible to walk on.

Some basic general guidelines for all types of metal roofs:

  • Always check the manufacturer’s advice on the recommended method of walking on a particular roof. Different companies make roofing systems different, hence the best way to ensure safety is by using instructions and illustrations from the manufacturer’s manual.
  • Use fall protection and all required safety equipment and check that it meets OSHA standards of safety.
  • Wear light-weight soft-soled shoes that are clean from any debris on the soles.
  • Never walk on gutters, eave flashings, rake flashings, or hip and ridge flashings.
  • Never walk on any skylights or fiberglass-type panels.
  • Choose the right weather conditions.

Wearing the Right Shoes

The right shoes offer grip as you walk on the roof. Unlike other roofing materials, metal roofs are very slippery and without the appropriate footwear, the likelihood of being unable to walk reduces drastically. This is why you need soft-soled shoes that are clean from any debris on the soles. 

Soft-soled shoes have a rubberized outer sole that offers grip and reaction as you walk on slippery or wet surfaces. It will prevent you from slipping, especially if it is a steep roof. Soft-soled shoes are also known to be lightweight. Having lightweight shoes will also allow you to maneuver comfortably on the roof. Better mobility and speed are excellent features. Avoid wearing heavy boots as they can obstruct your pliability and flexibility.

Choosing the Right Weather Conditions

Metal roofs can be very dangerous to walk on during the rainy seasons. In the winter, during hail storms, rain or thunderstorms, and earthquakes; all these weather conditions are not suitable times to walk on the metal roof. The metal will be extremely slippery and you are at increased of being hit by lightning.

Observing Safety Measures

Safety concerns are the number one measures one should even consider before attempting to walk on a metal roof. Note that other types of roofs are safe to walk on, but metal has its own additional risks, especially if it’s a steep roof. Therefore, you need fall protection guides ready to secure yourself properly while on top.