That is NOT how to clean moss of your roof!

First time home buyers are fantastic.  Never before have you had to do any kind of maintenance on the place that you were living.  If there was a problem you just called the landlord.

Now, you are going to be in charge of an ENTIRE house!!  It can be intimidating, especially after a good home inspection!  Not to fear you first timers, there have been lots of people in your shoes and many with even less technical understanding of the maintenance issues that plague your new home.

In the Salem, Oregon area one very common issue that will require attention is moss growth on your roof.  To be fair, this is not a life and death issue, however with less than a few hours of attention a year this issue can be effectively controlled.

Moss tends to grow in the shady sides of the home.  Mostly this has to do with the 8 months or so that your roof will stay wet in these areas.  This constant moisture creates an ideal location for algae population.  If moss is allowed to flourish unchecked it can create little pockets that catch and hold moisture.  Also the moss can actually begin to lift the shingles.  All of this catching and lifting will slow the water that is running down the slope and the longer water is on your roof the shorter the life of your roof will be.

Ok, we know that moss is not good but how do we control it?  Moss killer.

Moss does not like reactive metals like zinc and copper.  Commercial available moss killers like, “MossOut or any of the other sprays or powders are best.

  • The moss control measures that do not work or maybe work too well, at the expense of the life of your roof are: Strips of zinc that claim to leach onto the roof and kill moss continually.  These strips are good only in theory and only tend to protect about two feet of the down hill roof surface.
  • Also, moss will die if treated with laundry detergents, however laundry soaps have surfactants (read: de-greasers).  Composite shingles are made of asphalt (read: grease!).  These detergents can quickly chew holes in your roof!!
  • Power washers.  Please, please DO NOT power wash your composite shingle roof.  The idea behind killing moss is to prolong the life of your roof.  You will quickly shorten the life of the roof you are trying to prolong by blowing it to smithereens with a well meaning power washer.

3 comments

  1. You might want to add content on how to remove existing moss instead of just how to prevent. Mossout will kill it, but it still needs to removed.

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