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need a roofing expert

jammie

ganjatologist
Veteran
i use rainwater for my indoor dwc grow. the water coming off my new owens corning shingle roof has a ppm of 70 and a ph of 7 and i'm trying to figure out what that may be. the water coming off the old roof was barely 20ppms and a ph of 5.5. i let several rain showers wash it off before i started collecting again. the only thing i could find online is that shingles are made from asphalt and mica but i'm sure there's lots of other chemicals involved
 

coldcanna

Active member
Veteran
the contaminants that you could be worried about are the heavy metals and polyaromatic hydrocarbons from asphalt shingles and other contaminants that may deposit onto roofs from air. It appears that contaminants that rainwater washes off of shingles may be a significant source of surface water contamination. The contaminants that are washing off of roofs include zinc, lead, chromium, arsenic, and polyaromatic hydrocarbons. It is similar to what you might collect off of a parking lot.

http://tylertork.com/diyrainbarrels/safety.html

Sounds like something I'd stay away from, or at least run through some type of osmosis or filtration
 

marinemansf

Member
I used to collect rain water, but I would just put a clean bucket out when it rained. But after some research, learned it just makes for more work than its worth. Especially when your setup holds around 40 gals. Like mine.
 

jammie

ganjatologist
Veteran
thanks for the quik replies. coldcanna- that tylertork site was real helpful. between the silica and calcium in the mica and the heavy metals and toxins that are coming off the shingles maybe i could market this stuff as the next aptus. sorry couldn't pass up that dig. anyhow- ive been diverting rainwater into a 100 gal recylce container for the last 5 or so years and neverr had any problem til now. my grow is 30 days into flower and my house water isn't too bad. i only do one grow a year so i definately don't want to fuck up now. hopefully by next december the new roof will be flushed and good to go. i may come up with a 5 gallon bucket of finesand as a final filter. thanks again for the help!!
 

MJPassion

Observer
ICMag Donor
Veteran
thanks for the quik replies. coldcanna- that tylertork site was real helpful. between the silica and calcium in the mica and the heavy metals and toxins that are coming off the shingles maybe i could market this stuff as the next aptus. sorry couldn't pass up that dig. anyhow- ive been diverting rainwater into a 100 gal recylce container for the last 5 or so years and neverr had any problem til now. my grow is 30 days into flower and my house water isn't too bad. i only do one grow a year so i definately don't want to fuck up now. hopefully by next december the new roof will be flushed and good to go. i may come up with a 5 gallon bucket of finesand as a final filter. thanks again for the help!!


Follow the fine sand with a bucket of Activated Carbon.
The fine sand will filter the chunky stuff but I'm guessing it wont do much to stop the heavy metals and other chemicals that are being washed off the roof.


I'd also suggest having your water tested, if you really want to know what's in it.
 

Chunkypigs

passing the gas
Veteran
look around the houses where you live and see if the rainwater coming off the roof is killing everything or is it in overgrow mode from all that water?

nothing in shingles transfers to the water except what breaks off over time and it won't hurt your plants, rainwater off the shingles was all I used in Mass for 18 months and it worked fine.

ph perfect. happy plants.

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Ringodoggie

Well-known member
Premium user
Depending on where you are in the country, your shingles could also be treated with 'anti fungus' chemicals.

I picked up a couple quotes from roofing manufacturers' sites....

The most effective AM [anti-moss] shingles now have copper granules embedded in the asphalt shingle along with the normal granules.

“An active ingredient in many AR shingles is titanium dioxide.”

I know you're not drinking it but.... What I would be worried about is e coli contamination from bird poop. I know the birds like to do there thing on my roofs and I don't know if your proposed filter system would be able to treat this effectively.
If it was me, I would use the roof water for other purposes but not for drinking.

Never use runoff in overhead irrigation

Unless the zinc content is particularly high,

Rainwater runoff from your roof contains a mix of materials deposited by pollution and animals as well as chemicals used in the manufacture of the shingles. Fumes from industry and traffic pollution leave deposits of heavy metals, insecticides, hydrocarbons and other chemicals on the roof. Rainwater can absorb zinc, copper and aluminum from metal roofs as well as chemicals used for weatherizing and waterproofing asphalt shingles. Small mammals, birds and insects deposit fecal matter on the roof, along with the bacterial pathogens it contains.




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