Question

How can I control moss growing on my roof?

Asked by John Duke
Richmond, VA

I have moss starting to grow around some of the asphalt shingles on the north-facing roof of my house in Richmond, Virginia. It is still contained enough that I think I can take care of it myself, but I can see what is going to happen by looking at a neighbor's house if I ignore it. I have read about some methods of abatement, but none of them address the environmental impact or possible harm to the shingles themselves. I expect to have the roof for at least five more years before I replace it.

Answer

Answered by Erik Henry

Brownsburg, IN

ELH Construction LLC

September 11, 2012

Pressure washing lightly will remove the moss without damaging the shingles. Make sure to spray down the slope not up or you may cause a leak.

Moss on asphalt shingles indicates that organic material is collecting on the shingle giving the mold food to grow on. The overall slope of the roof may not be step enough for rapid draining and water is being retained on the roof.

  • Trees should also be cut back away from the home to allow sun to dry out roof shingles.
  • Shading, organic material collecting on roof, and a shallow slope to the roof can all lead to moss on roof.

Most importantly no chemicals are needed to solve your problem, just proper maintenance.

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