You want your tile roof to last a long time, but you also want it to look good for the life of the installation. Unfortunately, stains can sometimes affect the appearance of tile roofing. Understand what causes the stains along with how to prevent and remove them so that you can ensure your roof looks good for years to come.
Most tile roof stains are white. The cause of this is efflorescence, which occurs when the porous tiles absorb moisture. The moisture dissolves some of the minerals in the tiles and causes these minerals to leach out as white stains. In other words, the stains are little more than limescale.
Moss and algae can cause darker stains, typically deep green or black, on roof tiles. These stains are typically only on the surface of the tiles, although more porous tiles may absorb some of the stains if the moss and algae are left on the roof for long periods of time.
Prevention of efflorescence is best achieved by choosing high-quality roof tiles for your new installation. Higher-quality tiles, particularly those that come presealed, are less likely to absorb water and develop mineral deposits.
When it comes to moss and algae stains, the best method of prevention is to avoid the conditions that lead to their growth. Moss and algae prefers shaded areas with high moisture. If you trim back trees to open up the roof to light exposure and air circulation, you will likely have fewer moss problems.
Stains on a tile roof don't affect the longevity of the roof or how long it lasts, but that doesn't mean you want to live with them. Efflorescence is the hardest to remove because it will keep coming back until all the soluble minerals have leached out of the tiles. You can minimize the appearance of the white stains during the efflorescence period by scheduling an annual roof cleaning. Your roofer will use a lime removal product to clean off the surface stains.
Moss and algae stains also require proper cleaning. Bleach-based cleaners work well in this instance because bleach kills any remaining spores and removes the stains. Your roofer will take precautions to make sure the bleach cleaner doesn't run off the roof and damage the landscaping and plants below. It's best to have a roofer clean your tile roof, as trying to do it yourself is dangerous and can lead to tile damage.
Contact a residential roof company like SUNVEK for more help.