Some Really Bad Roof Stains in Cary, NC

Roof cleaning products that don’t work.

I was going through and cleaning out some of our roof cleaning pictures and came across this one.

You can see how dirty and stained this roof was before we cleaned it.  Towards the bottom of the roof line, you will notice the white, chalky substance.  I had never seen this on a roof and asked the customer if they had any ideas as to what may have caused it.

Any guesses?  If you said it was the remnants of a “gimmick” (my word not theirs) roof cleaner they had purchased at a local home improvement store, you win!

You are supposed to be able to spray this “eco friendly roof cleaner” on the roof and then forget about it.  Over a period of time, the chemicals will supposedly kill and remove the roof stains leaving your roof looking new again.  In this case, it was a couple of months old and did not look like it was working.  I would say it made the roof and the exisiting stains look worse.

There are a few of these roof cleaning chemicals for sale in both the box stores and on the internet.  They are touted as “safe”, “eco friendly” and a few other cool adjectives, but from doing some reading and checking out the MSDS sheets (These are the papers that list chemical components and ingredients) it looks like they may not be the “eco friendly” roof cleaner after all.   I am quoting a few excerpts from the MSDS sheets here:  “Corrosive to skin”  “Severe eye irritant” “Inhalation of mist may produce respitory irritation”  “May be fatal if swallowed” .

It makes me swear like a sailor!  It is fine to sell these roof cleaning products, but don’t pretend they are not dangerous by labeling them as friendly!  If it is (supposedly) going to kill off the algae on your roof, it needs to have some type of killing power.

This green cleaning is also making a push into the world of professional roof cleaning.  There a some companies out there that push the earth friendly version of cleaning your roof .  All they are really doing is spraying a sodium hydroxide based, or “oxygen cleaner” (really?) chemical onto your roof and then blasting it off the roof with a pressure washer.   I have this posted all over my site but it never hurts to repeat:  Pressure washers are not to be used for cleaning a roof. 

If a company is using any type of pressure washer to clean your roof, i.e. pressure washing wand or roof machine, they are working outside of the shingle manufacturers recommended methods for cleaning a roof and could very possibly damage your roof.

As stated in the link in the above paragraph, it is not so much that these machines loosen and blow of the surface granules, but that they break the seal that holds the shingles together and make your roof a “system” of protection.  Once these seals are loosened and broken, your shingles “flap” during any kind of wind event because they are no longer bonded to the shingle below them.

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