Ask a Mold Expert: What Do I Use to Kill Mold on a Roof?
We often get some very interesting questions from our members, and others in the building and construction community. We recently were posed one that we believe would be helpful for the public. A roofing contractor recently sent us this message:
“I saw your article about sodium hypochlorite not killing mold on asphalt roofing by Doug Hoffman. I am a soft washing and roof-washing contractor. I was never taught that it was mold on a roof. I always thought it was lichen, algae, and moss. Further, he said to use a biocide, and chlorine is one. Can I get some clarity on this? Who was told or tested roofing materials to see if the black streaks where mold? And if not mold why will chlorine not kill moss, lichen, and algae? Finally I read that chlorine will kill mold on non porous surfaces but it will not kill mold on porous surfaces?”
Our Executive Director, Doug Hoffman, had this to say in response:
“Great question! All of the chemistries that are approved by the EPA to kill mold (fungus) are registered with the EPA as pesticides. In fact, the LA Dept. of Agriculture requires licensed specialists of mold remediation San Antonio to also carry a pesticide ground-applicators license because, again, what they are using are pesticides. Sodium Hypochlorite is registered with the EPA as a disinfectant because it is good, as a sanitizer, on hard surfaces but will not adequately penetrate the mold to kill the “bio-slime” and actually eliminate it from growing. If you read the use instructions, it’s incredibly toxic and requires some dwell time to actually kill any of the microbiologicals it can address.
In 2004, Oregon State University performed A study to address this issue, and determined exactly what I wrote in “Mold-Free Construction” five years earlier (the first edition). Bleach will affect the discoloration (making it look like it disappeared) but will not actually kill the mold. Even when you add detergent and high levels of surfactants, it simply will not penetrate the mold. That’s why bleach should never be used on mold remediation projects either…people have been slow to come to the table but the science is proving this position to be right!
In regards to what is actually growing on the roof, that varies significantly based on geography. Moss is really bad in the Northwest US while mold is worse in the Southern states. Here’s the fact that needs to be considered: any microbiological contaminant will feed on the DIRT that is accumulating on the roofing system (from acid rain, settled dust, etc.) and, under the right conditions, its roots (depending on the type of mold) could grow into the shingle (especially asphalt shingles that have a lot of fillers in them and very little asphalt or petro product). Killing that growth is paramount to extending the life and improving the appearance of virtually any roofing system (even tile) and using a pesticide with surfactants that actually will penetrate that growth is best, by far!
BTS, I love the concept of “soft washing” (which is what we did with our company) to maintain the integrity of the ballast and protect the shingle from UV. BUT, experience has shown over and over again that bleach will only make it go “clear” and then it will reappear with a vengeance.”
Source: The National Organization of Remediators and Mold Inspectors (NORMI)
Note: Aspen Environmental Services recommends using a licensed and trained professional for testing and removal of mold on a roof or elsewhere for two main reasons: 1) to make sure that the mold is removed and won’t come back and 2) to protect against the use of toxic chemicals, which can be dangerous in the hands of non-professionals.
Aspen Environmental professionals are licensed and insured and members of the National Organization of Remediators and Mold Inspectors (NORMI), the National Air Duct Cleaners Association (NADCA), and the Institute of Inspection Cleaning and Restoration Certification (IICRC).
Contact Aspen for anything related to water damage cleanup, mold testing, mold removal, or air ducts: Call 978.328.0882 or email info@aspenenvironmentalservices.com.
Write more, thats all I have to say. Literally, it seems as though you
relied on the video to make your point. You obviously know what youre talking about, why waste your intelligence on just posting
videos to your blog when you could be giving us something enlightening to read?
0mniartist asmr
Appreciate the recommendation. Will try it out.
asmr 0mniartist
An impressive share! I have just forwarded this onto a coworker
who had been doing a little homework on this. And he in fact ordered me lunch due to
the fact that I stumbled upon it for him… lol. So allow me to reword this….
Thanks for the meal!! But yeah, thanks for spending some time to talk about
this topic here on your website. asmr 0mniartist
There is certainly a great deal to learn about this
subject. I love all of the points you have made.
asmr 0mniartist
I really love your website.. Very nice colors & theme. Did you develop this web site yourself?
Please reply back as I’m planning to create my own personal website
and would like to know where you got this from or
just what the theme is called. Appreciate it!
asmr 0mniartist
First off I want to say superb blog! I had
a quick question that I’d like to ask if you do not mind.
I was curious to know how you center yourself and clear your
mind prior to writing. I’ve had a difficult time clearing my mind in getting my ideas out there.
I do take pleasure in writing but it just
seems like the first 10 to 15 minutes are wasted just trying to figure out how
to begin. Any ideas or tips? Thanks!
Your method of describing the whole thing in this paragraph is
in fact nice, all can without difficulty know it,
Thanks a lot.
Hello there! Do you use Twitter? I’d like to follow
you if that would be ok. I’m definitely enjoying your blog and look forward to new updates.
Hi, i think that i saw you visited my website thus i came to “return the favor”.I’m attempting to find things to improve my
web site!I suppose its ok to use some of your ideas!!
Good post. I’m experiencing many of these issues as well..
Good replies in return of this issue with genuine arguments
and describing everything concerning that.
hi!,I like your writing so so much! share we communicate extra about your post on AOL?
I require an expert in this space to resolve
my problem. Maybe that is you! Having a look ahead to see you.
I was suggested this website by my cousin. I’m not sure whether this post is
written by him as no one else know such detailed about my trouble.
You are amazing! Thanks!
Awesome! Its in fact amazing piece of writing, I have got much clear
idea regarding from this paragraph.
If you want to get a good deal from this paragraph then you have to apply these strategies to
your won weblog.
scoliosis
I don’t even understand how I stopped up right here,
but I thought this post used to be good. I do not know who you are however
definitely you’re going to a famous blogger in the event you are
not already. Cheers! scoliosis