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Cleaning a shingle roof

Posted: Mon Jun 11, 2018 8:29 am
by Leftside
So I have a shingle roof. It has mold on it from pines that fall and tend to collect on the roof before they are blown off. I've tried a mold cleaner called, wet and forget. It seemed to help but i think becaise the mold is pretty caked on and built up, there is still a lot of mold on the roof. I was going to use some more wet and forget, but I would like more immediate results.

What can I do? I read that pressure washing can compromise the shingles. Is this true? Is there anything else I can do to quickly remove the mold?

Thx in advance.

Re: Cleaning a shingle roof

Posted: Mon Jun 11, 2018 2:00 pm
by A. Spruce
Can you post a pic? Sounds like you're dealing with moss, not mold, different beasts require different methods to eradicate.

Re: Cleaning a shingle roof

Posted: Tue Jun 12, 2018 6:39 pm
by Leftside
Here are some pics:

https://imgur.com/gallery/9YI4I1U

Hope the link works.

Re: Cleaning a shingle roof

Posted: Tue Jun 12, 2018 7:13 pm
by A. Spruce
Hard to see from the pix.

Pressure washing will blow the mineral coating off the shingles, the mineral coating is what protects the shingle itself from the sun, so don't pressure wash them.

You could spot test a bleach solution or something like Clorox Clean Up, but I think bleach alone will suffice, and it will be cheaper than anything else. You need to use caution, as bleach will kill plants and animals, so dilute it to use it, spray it on a test area and wait 15 to 30 minutes, then rinse well with a garden hose.

The test is to confirm that it is not damaging the shingles and that the bleach is actually killing and removing the mold. If the test goes well, do a larger area.

Re: Cleaning a shingle roof

Posted: Tue Jun 12, 2018 7:26 pm
by Shannon
I would use a 50/50 water bleach mix. Spray the roof and let sit for 10-20 mins and then rinse with garden hose. Like Spruce said test it first and also be sure it is not running down your exterior siding and bleaching it as you rinse.

Re: Cleaning a shingle roof

Posted: Wed Jun 13, 2018 6:12 am
by Leftside
Thanks. It looks worse from the street, but basically it looks like a black coating on the roof.

It does look like the wet and forget has worked a bit since the roof had darker black areas.

I'll finish my wet and forget and test out the bleach. Thanks again.

Re: Cleaning a shingle roof

Posted: Wed Jun 20, 2018 7:23 pm
by Leftside
So this turned my rooof a darker brown copper color. Odd thing is, i sprayed in an inconspicuous corner and all went well. Sprayed more near the corner and it still looked good.

I decided to spray more areas. In the front of the house, I hit some moldy/mildewy spots and it turned copperish. I thought it was because it was wet so I left it. Lo and behold afrer rain it still remains a dark copper color.

It's not horrible, but it is annoying. I am not sure if it is the mildew changing color or if the roof changed. I guess time will tell. The back corner still looks like new. In fact other areas in the back that I sprayed look fine. Maybe different type of shingles, lighting? I dunno. I'll report back if anything changes. Sigh.

Re: Cleaning a shingle roof

Posted: Wed Jun 20, 2018 10:56 pm
by Shannon
Seems strange but no going back now.