Products for Cleaning Barrel Tile Roofs

Barrel tile roofs can grow all kinds of vegetation. tiled roofing image by Daria Miroshnikova from Fotolia.com

The black stains on roofs that build up gradually over time tend to escape a homeowner's notice until the stains are visible from a distance. Although most barrel tile roofs are alkaline and often prevent the colonies of algae from forming, those black stains can happen, especially during the rainy season. A few different chemicals are used to clean barrel tile on roofs; the ones you need will depend on your roof.

Commercial Proprietary Blends

Hundreds of products on the market claim to be the "safe" or "green" way to clean a roof, and some people have had success with them. Usually sold as a concentrate or a powder, these products require you to mix the chemicals yourself using diluting instructions on the package, and most are designed to be used with a pressure washer. While the chemical content of these products vary, most roofing professionals recommend against them because they are no more effective than bleach and are much more expensive. If used improperly, they can damage gutters, trim and landscaping.

Bleach Solution

Roofing professionals recommend a 1 percent bleach solution to clean moss, mildew and algae off barrel tile roofs. The solution can be sprayed on and left for five to 15 minutes to allow it to kill the organisms, after which the whole mess can be easily rinsed from the roof with a regular garden hose. Some people prefer to scrub the tiles with a wire brush, thinking that it will remove the stains faster, but the organisms will not release their hold until they are dead, and a harsh scrubbing could damage the finish on the tile. Allowing the bleach solution time to work is not only more effective, but easier as well. As long as the solution is a very diluted 1 percent, it will not harm gutters or landscaping if rinsed thoroughly. In fact, a proper rinsing process will actually water any surrounding plants.

Water-Only Pressure Washing

To clean a heavy buildup of lichen or moss, a pressure washer may be necessary, but should be used without chemicals. The bleach solution method should be done first, and the roof should be rinsed with a regular hose. If thicker, more advanced colonies of lichen or moss do not wash away, a water-only pressure washing will help pry their roots from the tile after the bleach has killed them. If the roof is not stained, but is simply dirty or dusty, a water-only pressure washing will clean it quickly and effectively.

References

• Oldcastle Precast Westile: Wes Answers Your Questions
• Practical Pressure: Do Tile Roofs Need to be Pressure Washed for any Reason Other than Maintaining a Clean Look?
• Roof Cleaning Chemicals and Products Guide