[youknowhow]

Does anyone know as how to remove green stains out of roof? I've heard power wash could damage the roof and chemicals are much better. Any positive experience with particular chemicals? I appreciate for sharing it here. Thank you in advance.

[tickle]

Why do you want to remove the green stains. These could possibly be algae caused from overhanging trees. I have that as well on one part of my roof and really wouldn't think of trying to get rid of it, although my roof will be done in just a month or two, so it doesn't concern me.

However, using chemicals to remove this stain is not a good idea as it would probably have some serious side effects running off the roof when you apply it. As for power washing, yes, that could do some damage but only if the pressure is extremely high such as an industrial power washer might project. There are power washers available for rental that are used for cleaning jobs on the exterior of homes and you could possibly look into that, but I wouldn't be surprised if your whole roof doesn't need re-doing if you have green algae already developed to the point where you can see it, IMO.

[Chery]

Algea and/moss is nature's way of telling you the air is healthy enough to breathe.. they don't survive when the air is full of gases and other stuff that can harm - so be glad the air is healthy for you as well.

Chemicals are not a good idea, try a biodegradeable cleanser like quick & brite.

Good luck and good health

[youknowhow]

Alas! The insurance company thinks different: all destroying factors should be removed from the roof.
Also I see from Wikipedia:
Algae (singular alga) are groups of relatively simple living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic matter.

Converting inorganic substances (roof) into anything else means destroying. I want to keep the roof longer, so I think all plants should be removed. How? That's what I am trying to figure out.

[Chery]

Alas! The insurance company thinks different: all destroying factors should be removed from the roof.
Also I see from Wikipedia:
Algae (singular alga) are groups of relatively simple living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic matter.

Converting inorganic substances (roof) into anything else means destroying. I want to keep the roof longer, so I think all plants should be removed. How? That's what I am trying to figure out.

I think it is a type of moss, not algea. Nevertheless, if you need something safe to get rid of it, check this site out. I've used this for over 30 years and I know what it can do. This is not an advertisement and I get nothing for it. I just like it and use it myself.

Quick'n Brite | Commercial Uses

[ballengerb1]

Definitely do not use a power washer, it will tear up the shingles and break the seals. Most big home center sell a product made specifically for removing moss from a roof. Do not buy any things else. The products I have bought at Home Depot do not harm plants so be careful to read the label and follow the instructions. Moss will definitely shorten the life of your roof so you are correct in trying to remove it. You may also consider install a strip of zinc along your ridge line. Rain water on the zinc will cause the shingles to be less inviting to future moss growth, usually prevents new growth completely.

[glavine]

The pressure washer... thats great id love to see that, but not on my house. I've never used zinc, but ballengerb1 seems to have a vast knowledge of just things I don't know, lol
When I've had to clean it I've watered down chorox bleach, and used a bug sprayer, I've let it set for 10min no more and spray it off with a water hose. If its hot I don't let it set that long

[Kstar4u]

I would recommend contacting a professional service that specializes in addressing your problem/concern. You can probably get the answers to what exactly is causing the stain and advice for properly treating the condition (most likely at no cost). You may find that it's more cost-effective to use them to deal with the situation, than if you were to do it yourself. I would imagine that whatever solution is used... the primary concern will be to avoid damage to the roofing material (and the integrity of the roof itself) as well as any impact on the environment... it's even possible that some effects to the environment (not just in your yard) may not be evident immediately, but will cause problems later.

Please be careful when/if you choose to use chemicals that are not normally used for that purpose.

Good luck.