Sphagnum moss is a large category of moss that has up to 300 varieties. It is well known for its ability to retain water indefinitely, creating whole environments within. This moss can find its way onto roofs that don't have adequate ventilation, causing damage to the home. It is an easy-to-remove moss that is easily deterred by herbicides.
Home's Roof Damage
Mosses that grow on the north-facing roofs without adequate ventilation must be removed. The moist conditions of roofing materials without exposure to sunlight is a perfect growing environment. As the moss grows and the roots develop they can deteriorate the roofing and increase leaks. Preventing moss growth will prolong the life of the roof.
The first step to removing sphagnum moss from the roof is to physically gather and dispose of the large pieces into a compost before applying the herbicide. It is important to avoid clogging the home's gutter system while removing the moss. Blocking the downspouts can lead to overflowing of gutters and future water damage to the roof.
Herbicides containing zinc sulfate and potassium salts or chlorine bleach are highly effective at killing moss, according to research done at the Oregon State University. After physically removing the largest pieces of moss, cover all vegetation beneath the roof to protect it from unwanted herbicidal damage. Spray the roof surface with a mixture of herbicide through a pump spray. Start at the tip of the roof and work your way down the house.
Increasing airflow by cutting back nearby trees will help cut back on the amount of chemicals and time spent removing moss. Homeowners can also install zinc strips at the peak of the roof to eliminate moss growth as a slow-release herbicide. It is important to spray all new moss patches immediately upon development.
Herbicidal sprays can easily transfer from one location to another through wind and precipitation. Homeowners should avoid applying herbicides during weather that can possibly carry nonselective herbicides to the lawn or garden. All other manufacturer guidelines should be carefully followed, as herbicides are highly toxic in nature. Avoid spraying with young children or pets anywhere near the area.