Cleaning Lichens from Shingles (An Experiment)

Posted by in Buying/Maintaining a Home, Roof, Shingles | October 05, 2015

While performing my annual pre-winter roof maintenance this fall I again noticed the moderate growth of lichens on parts of my roof.  The lichen growth is in areas that are heavily shaded (Figures L-1).

I thought that this might be an occasion to clean them off and give a report of my findings.

Figure L-1  Lichens on my roof.

Figure L-1 Lichens on my roof.

I thought it would be relatively easy and got a broom out to wisk them away, but to no avail.  I then got a stiff brush that I thought would remove the lichens, but not remove the granules.  Again I met with failure.  I then brought out an even stiffer brush and applied a little elbow grease.  By then I thought I could hear those darn lichens laughing as they remained in place.

I was now desperate and a little miffed at those little buggers. I went and got THE STEEL WIRE BRUSH that I had been using for an on-going painting project.  Surely, they can’t resist the power of a STEEL WIRE BRUSH!

I was still hesitant at using the STEEL WIRE BRUSH, but I had no other choice: I was NOT going to bring out the power washer – I’ve seen what a power washer can do to a wood deck and a concrete driveway, but those are another story.

I began to brush lightly and began to seen some progress in removing the lichens.  I also noticed that the granules were still holding fast, so, I pushed down a little harder.  Soon the lichens were disappearing before my eyes (Figure L-2).

Figure L-2 Brush lichens with a wire brush.

Figure L-2 Brush lichens with a wire brush.

I stopped on occasion to assess the granule loss, but I could not see any significant wear.  Soon those dreaded lichens were gone (Figure L-3).

Figure L-3 Shingles cleared of lichen growth.

Figure L-3 Shingles cleared of lichen growth.

Now, my colleagues tell me that I should warn you, “DON’T TRY THIS AT HOME! THIS UNDERTAKING WAS PERFORMED BY AN EXPERT AND IMITATING THESE ACTIONS COULD CAUSE DAMAGE TO YOUR ROOF!”  And they would be right.  I still can’t belief that it worked so well.

As a follow-up I plan to regularly examine the area where I removed the lichens to see how long it takes for them to return and to see how well the shingles hold up and report back to you.  So stay tuned.

 

Disclaimer