What Chemical Should I Use to Remove Lichen From Terracotta Roof Tiles?

Made from a ceramic clay featuring a reddish colour, terra-cotta roof tiles bring an old-world atmosphere to your home. Like other materials, terra-cotta is not immune to lichen growth. The lichen will trap moisture, increasing the chance of mould growth. Fortunately, several cheap and common items will remove the lichens from the roof without harming the terra-cotta tiles.


The pungent, all-natural liquid will remove lichen from terra-cotta roof tiles. Furthermore, vinegar eliminates any odours that may accompany the lichen. Use 2 cups of white vinegar for every gallon of water. Alternatively, fill a spray bottle with undiluted white vinegar and thoroughly saturate the lichen with the pure vinegar.

Oxygen Bleach

Like chlorine bleach, oxygen bleach will remove fungus from various surfaces. However, oxygen bleach will not damage or discolour terra-cotta as chlorine might. Furthermore, oxygen bleach does not contain harsh chemicals and is safe to use around people, pets, wildlife and vegetation. Pour 1 cup of powdered oxygen bleach into 1 gallon of cool water. Mix with a long-handled spoon for several seconds until the powder dissolves.

Lichen Removal

Place a bucket filled with either the vinegar or oxygen bleach mixture and cleaning tools next to a ladder propped up against the house. Carefully gain access to the roof via the ladder. Dampen the roof tiles thoroughly with a water hose. Use the pressure from the water to push loose debris --- such as sticks, leaves, moss and lichen --- off the roof. Start at one end of the roof and submerge a brush broom into the mixture. Scrub the roof clean with the cleaning solution. Pay attention to your surroundings while on the roof. Never get too close the edge of the roof, and take your time. Rinse the terra-cotta roof tiles clean with the hose.


Refrain from using abrasive cleaners or those high in acid or ammonia to clean terra-cotta items. These items can damage, scratch and remove the terra-cotta sealer. Furthermore, never use hard-bristled scrub brushes or other cleaning tools that can scrape and scratch the clay. A roof can be a dangerous place and you must take great care to prevent injury to yourself and others while cleaning it. Wear a pair of shoes that have good traction to help prevent slipping while on the wet roof. Also, have at least one other person on the ground while cleaning the roof. This person will help hand the cleaning tools up to you, hold the ladder steady and be there in case an accident occurs.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Amanda Flanigan began writing professionally in 2007. Flanigan has written for various publications, including WV Living and American Craft Council, and has published several eBooks on craft and garden-related subjects. Flanigan completed two writing courses at Pierpont Community and Technical College.