Posts: 29,852
Threads: 0
Joined: Jan 2008
Location: Mid-MI
(02-22-2018, 09:13 AM)ChcukO1234 Wrote: I have a 40 year asphalt shingle roof about 18 years old. We have a shaded lot.
The section that faces east is covered with a greenish stain which is annoying LOML. Can treat this myself by spraying on an algicide or similar, or is this a job for pros? Is there anything to avoid using that would shorten the roof life or cause premature shedding of the roof grit?
Thanks in advance.
Chuck O
https://www.thisoldhouse.com/ask-toh/get...-moss-roof
Mark
I'm no expert, unlike everybody else here - Busdrver
Nah...I like you, young feller...You remind me of my son... Timberwolf 03/27/12
Here's a fact: Benghazi is a Pub Legend... CharlieD 04/19/15
Posts: 18,250
Threads: 0
Joined: Jul 2002
Location: Ohio
I've had good luck with
This stuff on my siding. I've also heard pool shock works well - which would be similar to the bleach recommended by TOH in the article linked by Cletus.
Posts: 12,476
Threads: 0
Joined: Aug 2003
Location: Wapakoneta, OH
3 Houses ago we were living in the woods with the problems you get with a shaded roof. I used household bleach to kill, and found I had to retreat every other year or so. Small tip: do not let it drip down, like onto someone's clothes or something...don't ask.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
Posts: 106
Threads: 0
Joined: Nov 2008
I had a similar problem on the north side of our roof, although maybe not as bad as you describe. I applied a product called "wet and forget" with great results. You mix it w/ 5 parts of water and apply by spraying. I used a pump type garden sprayer which meant being on the roof, a process I no longer enjoy. If I have to do it again, I'll try a super-soaker from the edge of the roof at gutter level. It took a few weeks for the stain to go away, but it did work. ronwhit
Posts: 267
Threads: 0
Joined: Jan 2007
Location: Warrenton, MO
I too use
Wet and Forget on my roof, vinyl siding, shadowed deck and other stuff that gets green. Using bleach is not good for your roof or your gutters. It is corrosive and does not last well. Can't use it on your siding either. I sprayed my roof three years ago and it's just now starting to need a another treatment. My neighbor uses bleach and does it every year I think.
Was living the good retired life on the Lake. Now just living retired.
Posts: 5,732
Threads: 2
Joined: Dec 2004
Location: Fort Worth
There are zinc strips you can add to the shingles. Rain water spreads a tiny bit of zinc on the roof and inhibits the growth.
Posts: 3,146
Threads: 0
Joined: Mar 2003
Location: Litchfield County, Ct
A few years ago I think Mags recommended a product called
Spray and Forget.
It takes up to a month or two for the algae and stains to disappear, but then they stay gone for a long time. Every 2 years I spray again and none of it has returned. It's also non- corrosive to your roof, unlike bleach.
Following the directions is key. I highly recommend.