Slate Roof Cleaning & Maintenance
Slate is one of the oldest, longest lasting, and most durable roofing materials. Unlike most roofing materials, slate takes a very long time to weather. However, the older the slate tile is, the more fragile the tile becomes. Here are some tips for caring for your slate roof:
- Just because slate takes longer to weather than most other roofing materials, it does not mean that it is immune to organic growth. Moss, mildew, and algae are the most common growths seen on slate roofs. For the most part, this growth is not harmful to the slate, but it can lead to damage to the underlying wood sheathing. The continued presence of organic growth prevents the slate from drying completely after a rain. This lasting moisture will eventually make its way underneath the slate to the wood sheathing, causing the wood to eventually rot. For this reason, any organic growth should be cleaned off a slate roof.
- To help prevent the growth of moss, mildew, and algae from forming on a slate roof, it is important to keep shade and debris off the roof. The best way to do this is to either keep tree limbs trimmed back and away from the roof, or to remove any trees that cause excessive shade or frequently drop debris on the roof.
- No one should ever walk on a slate roof. While slate is a durable roof material, the older the piece of slate, the more fragile it is. Most slate roofs tend to be older, so it is safe to assume that any slate roof is fragile and prone to damage. Any form of weight can crack or break a slate tile, so no homeowner or roof cleaning professional should ever walk on the roof. When having the slate cleaned, it should be only be done from a ladder or lift to avoid damage to the roof.
- Because of the possibility of an older and fragile slate roof, no pressure should ever be used during cleaning. Any pressure greater than a garden hose pressure poses the risk of damaging the slate and/or the sheathing underneath. Pressure can force water under the tiles and onto the wooden sheathing, potentially leading to future mold and fungi problems.