Replies

1. 
   ChicagoMike | Apr 19, 2007 03:40am | #1

   I have heard of the same thing. I also have seen zinc coated metal strips applied to the roof to prevent it from coming back.

2. 
   junkhound | Apr 19, 2007 03:57am | #2

   I've used 3500 psi, 4 GPM pressuer washer with 25 deg nozzle with good effects on own roof.

   If the moss is thick, it will just roll off, if thin, it is much more tenacious.

   You can alway leave it on for effect <G>

    

1. 
   redtoolbox | Apr 19, 2007 04:01am | #3

   Where should I position myself to fire the hose. I am not big on heights.

1. 
   junkhound | Apr 19, 2007 04:09am | #4

   I am not big on heights.

   Only way it has worked for me is to be ABOVE where you spray, which means you need to walk the roof ridge.

   There are guys in the Seattle area make their entire living pressure washing moss.

   My roof is 30 ft up, but is only 3/12.  I use a 100 ft 3/8 hose to the PW on the ground.

   YOU NEED TO BE CAREFUL OF THE THRUST FROM A PW ON A ROOF, IF NOT USED TO THE THRUST, YOU CAN GET PUSHED OFF THE ROOF  (dont ask how I know that <G>)

   Edited 4/18/2007 9:09 pm ET by junkhound

2. 
   mojo | Apr 19, 2007 02:01pm | #6

   "You can alway leave it on for effect <G>"

    

   lol.  They are paying big money for 'green roofs' down in NYC.

3. 
   JDRHI | Apr 20, 2007 04:28pm | #8

   So thats where "the sun don't shine".

   J. D. ReynoldsHome Improvements

    

    

3. 
   pacificsbest | Apr 19, 2007 07:26am | #5

   Here in Seattle, as the last poster mentioned, you see every other roof covered with moss. It's mostly sections of roofs that don't get a lot of sun (that's when the sun is out this time of year!).

   If you pressure wash, be carefull with the pressure and the age of the roof. The best way to prevent moss is spreading on products such as "Moss-away" once a year. You might find it in garden sections at stores where you live.

   Be carefull up there, it's slick!

   Well, Guess I have to learn how to do THAT, now!
4. 
   alanj | Apr 20, 2007 05:50am | #7

   Hi, Red

   Just dealt with that problem. Our insurance co. insisted on a visual inspection on our house a while back. He flagged a roof on the north side of the house as being "at risk" because of a little moss.

   I used some lawn type moss killer that came in a gallon container with a lid designed to be attached to a hose. I poured the solution into a pump up garden sprayer, diluted it with water, (about 3 to 1, I think this was pretty strong), and soaked down the roof from a bedroom window that overlooked this shed roof. This roof is pretty small, about 10 by 12', so the little sprayer worked great and it blackened and killed the moss in just a day.

   I just looked at the container and it is "Rapid Green" brand moss killer but I imagine there are many others.

   I used the little sprayer to avoid ladder work and overspray. The instructions say to avoid cement products and we have an interlocking brick patio below.

   Edit to add: I think a pressure washer would take a few years of life from most roofs. Certainly so if asphalt or wood. Should be okay if you're lucky enough to have slate.

   Good luck

   Alan

   
   

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   Edited 4/19/2007 10:58 pm ET by Alanj

5. 
   fingersandtoes | Apr 20, 2007 06:33pm | #9

   Many commercial moss killers will damage your asphalt shingles. The best solution, which is recommended by most manufacturers, is to sprinkle Tide with Bleach on the roof. It must be done in sunny weather and left for at least three days before you spray it off. Any moss which is left comes off easily by rubbing it with a gloved hand. Using a pressure washer is iffy as you can remove a lot of the shingle's aggregate, which will shorten its life.