Moss

Moss is probably the easiest growth to identify. It can range in size from small to large clumps of furry growth. While moss doesn’t have roots, it has tiny protrusions that appear like roots, it will form its own soil by collecting dirt and debris from the surroundings. Cleaning moss off roof is generally best done as soon as possible before this soil has a chance to gather.

Lichen

Lichen is actually a combination of algae and fungi living together. It usually looks like a green crust that grows in patches. While moss can look quite luscious, lichen usually grows much thinner and closer to the surface of your roof. Lichen on your roof is particularly unpleasant to the eye and is best handled before it has a chance to fully take hold.

Mould

When mould is growing on top of your roof, it is often indicative of problems that started within the home. Mould is the most dangerous type of fungi that can grow on your roof because it’s hazardous to your health. This type of fungus is slimy and black, brown, or dark green. They both tend to appear as streaks of black or greenish colours. Underfoot it can become very slippery and dangerous to walk on.

Algae

The black mould-like stains and streaks that appear on your roof, particularly light-coloured. Found in climates with warm, humid summers, it doesn’t cause damage to the roof but it’s unappealing to look at. Algae does not have roots or leaves like other plants. Roof algae can develop in certain environments. It thrives in humid atmospheres, where heat and moisture combine. It can grow the quickly in shady, damp areas, such as the shaded sides of the roof and under large trees. It also needs nutrients to continue surviving on your home. 

Most cases of roof algae or fungus start with a single spore finding its way to your home. The wind can blow a spore onto your roof, and from there it will take off if the conditions right. Rainy weather can increase the chances of algae development, but it does not need rain if there is enough humidity in the air. 

Overhanging branches, blocked gutters, standing water, porous roofing material and poor roof ventilation can all cause algae. Taking steps to maintain your roof of these common issues can help you stay ahead of the game.

Mildew

When mildew appears in your shower, it’s unsightly and can be hazardous to your health, and mildew on your roof is no different. Roofs that don’t have good drainage systems are prone to mildew, which spreads rapidly in warm, wet areas. Mildew is usually light gray, pink, or black.

Dirt/Debris

A little bit of dirt/debris in the wrong location can do a lot of damage. It is important to prevent water from backing up into the building, causing leaks, rot and/or damaging the roof or interior of the home.

Not all stains can be entirely removed, however they can be treated to look less obvious. Some of these include Oils, Saps, Rust stains, Tannin stains and Bore stains to list a few.