Change Your Home One Step at a Time

Change Your Home One Step at a Time

Slate Roof Moss Removal Mistakes To Avoid

by Aiden Carroll

If you have a slate roof on your home, then you can expect the shingles to last between 50 and 200 years. Some shingles may need to be replaced over time by a professional due to cracking concerns, and maintenance is required to keep the slate in good shape. Proper cleaning is required though, or you may prematurely age the roof. This means that you need to avoid some common moss cleaning mistakes like the ones listed below to care for your slate roof the right way.

Mistake #1 - Using a Power Washer to Remove Moss

Moss often grows on roof materials like slate, because roof structures are directly exposed to rainfall. The humid conditions along with shade provided by trees creates the perfect environment for moss to thrive. Some people think they can simply remove the moss from the roof to clean it properly. Power washers are often used to force the plant material away.  

Unfortunately, slate is a mildly porous material. Porosity can vary depending on the presence of pressure, heat, and friction during the formation process. The porous nature of the material means that spores will line the small openings within the stone and moss will form again soon after removal. Also, pressure washers release between 1,500 and 3,300 pounds of pressure per square inch. The pressure can force water underneath the slate tiles and it can force flashing off the roof. This can lead to damage and leak concerns.

What Should You Do?

If you want to get rid of some of the moss on your roof, then use a regular hose to rinse the loose plant material away. Afterwards, consider trimming trees so your slate roof is exposed to the sun for a portion of the day. This will dry out your roof and keep new moss from forming. You should trim your trees properly though, so branches do not fall on your roof and cause slate shingle breaks.

You first need to identify the branches and leaves that are preventing the sun's rays from reaching the roof. When you locate these branches, also find branches on the opposite side of the tree that can be trimmed. This will balance out the shape and weight of the tree so it will not fall in the future. When you find all of the branches you want to prune, make sure they do not make up any more than 10% to 25% of the entire growth of the tree. Otherwise, you may end up killing the tree due to aggressive pruning. Also, minimize the number of large branches you remove.

You also should use sharp cutters when you prune and it is best to leave a one-half inch stub at the end of each branch so the tree can heal itself.

Mistake #2 - Using Metal Moss Killing Agents

If you are in a hurry to get rid of the moss on your roof or if you cannot trim trees away from your home, then you may turn to commercial moss killing agents to get rid of the plant material. Many of these products contain zinc sulfate, copper, or iron. These substances will likely kill the moss, but the metals are toxic when they are rinsed off your home.  

The products can then kill insects, fish, and plants that are growing in the area. Also, the chemicals can cause eye irritation. In some instances, the moss killing materials can stain your slate roof as well and weaken the shingles. Stains may be permanent and you may need to replace weak tiles.

What Should You Do?

Instead of using chemicals to kill the plant material on your roof, consider using natural substances instead. Materials like baking soda and vinegar are often just as effective as chemical agents and they are gentle on slate and the environment. Baking soda can be spread directly on the moss with a broom. The powder material will absorb most of the water from the moss and your slate roof and kill the plant material. Once the moss turns brown, you can use a rake to release the dead moss.

Vinegar can also be sprayed directly on the moss to kill it. The acetic acid in the fluid causes the plant material to die, and it also kills spores that may remain on and within the slate shingles. Undiluted vinegar can be used, or you can use a 50% mixture of vinegar mixed with water.

If you have a slate roof, then proper care should be provided. Moss may grow on the shingles, and you may mistakenly damage the slate by trying to get rid of the plant material. Use more information and the tips above to avoid these mistakes and to kill the moss effectively.


About Me

Change Your Home One Step at a Time

The best way to handle major home renovations is to take them one step at a time. Instead of trying to change your whole home at once, start small. I started with the guest bathroom, then the guest bedroom, then moved on to my kids’ rooms, my bedroom, and the living room. Now I’m working on remodeling the kitchen. I started this blog to help other people who are attempting major home renovations. I’ll show you how to change your whole home by breaking it up into manageable chunks. Wondering which kitchen counters are right for you, or how to add more space to your bedroom? We’ll go over the pros and cons of different materials and discuss DIY renovation projects. Before you know it, you’ll have created your dream home.