+- Woodnet Forums (https://forums.woodnet.net)
+-- Thread: roof cleaning (/showthread.php?tid=7378516)
roof cleaning - fixtureman - 05-17-2025
I have a shop with a metal roof that has black algae on it I was wondering what is the best way to clean it.
RE: roof cleaning - EightFingers - 05-17-2025
In Hawaii, they power wash metal roofs.
RE: roof cleaning - JosephP - 05-17-2025
I would try this:
https://bioadvanced.com/2-in-1-moss-and-algae-killer-and-cleaner.html?typesimple&&bvstate=pg:2/ct:r
It works great on vinyl siding.
(I just saw the page says "apply every 2 weeks"...more like 2 years. I guess if it doesn't work the first time, give it 2 weeks, then try again).
RE: roof cleaning - fredhargis - 05-18-2025
I used "Wet and Forget" on our single roof, and it really worked well to clear the black algae. What I'm not sure of is when you would apply it to a metal roof, it has to sit for a little while and the metal roof may get warm enough to evaporate it off. Still, if you can figure out when to apply it, it works very well and is truly wet and forget. It did take a few weeks to clear our roof, but it kills all forms of moss and algae. In fact I missed a few places so now I have to go back and treat the areas I missed. I think there are similar products available, but this was recommended here some eyars ago, I tried it and stick with it. It also did a great job on the vinyl siding on my shop building.
RE: roof cleaning - JosephP - 05-18-2025
(05-18-2025, 05:16 AM)fredhargis Wrote: ...What I'm not sure of is when you would apply it to a metal roof, it has to sit for a little while and the metal roof may get warm enough to evaporate it off. Still, if you can figure out when to apply it, it works very well and is truly wet and forget. ....
Rainy day. Quits raining at the end of the day but still overcast (so roof never got hot). Hit it right before dark and let it sit overnight.
RE: roof cleaning - fixtureman - 05-21-2025
I had a Morton rep come out and asked him what to use and he couldn't recommend any product and said they could come out and hand wash it. When I asked for a quote he said he would work one up for me and email it. well he did email me but he said that they don't do that and he quoted me a price to replace it. The price was more then double what I paid for the barn to begin with. I did try wet and forget but that didn't touch the black algae. I can use a soft brush to remove it but My wife doesn't want me on the roof as I am 76 and she thinks I will fall.
RE: roof cleaning - EightFingers - 05-21-2025
Your wife is right, a wet metal roof is slick as ice
RE: roof cleaning - Snipe Hunter - 05-27-2025
Zinc strips. Thank me later. Be patient
RE: roof cleaning - Roly - 05-27-2025
(05-27-2025, 03:47 PM)Snipe Hunter Wrote: Zinc strips. Thank me later. Be patient
I thought of that also but was wondering since the metal roofing is shaped would the zinc only flow at the bottoms of the grooves ? Roly