# Cleaning a metal roof?



## Rockrz (Mar 16, 2013)

Anybody know what the best way is to clean a metal roof that is under a tree where there appears to be mold on top of the roof?

Is cleaning even recommended using a high pressure washer?
I'd be wondering if it'll make the roof leak.

And how heavy can a person be and safely walk on a metal roof? 

If it can be pressure washed, is there any spray on treatment (like a clear coating of some kind) that would make the metal roof resistant to allowing mold to again grow on it in the future?


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## oldognewtrick (Mar 16, 2013)

How steep is the roof?


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## JoeD (Mar 16, 2013)

If the roof is a painted or baked on metal finish I would think a pressure washer same as used for your car would be just fine.


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## Rockrz (Mar 17, 2013)

It's normal pitch, and it does appear to be either a painted or baked on finish, although the neighbor across the street says it's older than 20 years (he said he remembers when it was installed.) 

Any idea if there is a coating that can be sprayed on after it's clean to make the surface resistant to tree sap and mildew?


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## Rockrz (Mar 24, 2013)

OK, thanks... I'll keep looking.

Maybe nobody here has experienced the need to clean a metal roof yet.


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## oldognewtrick (Mar 24, 2013)

As Joe said, it won't be much different than pressure washing a car. Be careful around any penetration or roof flashing that you don't damage them. The roof will be slippery, especially when wet. Get a safety rope or if you have access, a safety harness, cause gravity will always win...be careful.


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## Rockrz (Mar 24, 2013)

I understand that, I guess I'm really more interested in finding some sort of coating to put on it to make it resistant to mildew and tree sap.


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## oldognewtrick (Mar 24, 2013)

I am in the roofing business and have never encountered a algae or fungus resistant coating for metal roofs. Not saying its not out there though.


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## Rockrz (Mar 24, 2013)

It might be a good idea for a new product... I'll have my people develop that, patent it, and post the website here once it's ready to be put on the market


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## Rockrz (Apr 12, 2013)

Thanx!  This is what I was looking for....



> *Cleaning the Mold & Mildew*
> 
> Mix ½ cup of tri-sodium phosphate (TSP) in a gallon of water. If needed, increase the amount while keeping the same proportion of water and TSP in the solution. TSP is available in all the paint stores. Use a bucket for carrying this solution. Now take a soft brush, dip it into the solution and start scrubbing the areas with mold and mildew. Repeat this process until the area becomes free from mold and mildew. Then rinse the area with water to clean it properly. Minutely observe the roof after drying. If necessary, you can repeat this step. Remember, this step needs a lot of patience on the part of the cleaner.


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## WindowsonWashington (May 31, 2013)

TSP as mentioned.

A metal roof will usually take much longer to form algae/mildew.

Clean it before trying to apply some coating that might interact with the finish and degrade it.


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