Pond Boss Forums INTRO Questions & Observations EPDM Roofing material really lethal to fish?

One source tells me the EPDM roofing material is lethal to fish due to flame retardant and algaecides. And of course the water garden catalogs tell you it's bad for fish too, but the mark up is so much higher on the pond EPDM material you have to wonder if this isn't a marketing ploy. I have purchased both and they look identical to me. Of course I can't see the chemicals!

I do know in Steve VanGorder's Small Scale Aquaculture Book he soaks or scrubs a swimming pool liner to make it suitable for fish.

If there is indeed flame retardant or algaecide on the EPDM roofing material I would think it would not be in it but on it, and one could soak it for a while or scrub it down too?

Anyone know?

The reason I am asking this is I am seriously considering lining one of my small ponds due to a dike that is seeping a little. It's not bad enough to worry about water loss, but it creates a wet area on my neigbor's property and the EPDM material I trenched recently to create a barrier may not work. Seems the water is stopping at the barrier and then going up,and/or going under and then up. Maybe more fill on top of the trench area? I wish I could have buried the barrier more than 2 to 3 feet but it wasn't possible to dig the trench that deep.

I've emailed the Firestone company and am waiting for a response. However something tells if by some possibility the roofing material would suffice the company won't rat on the pond suppliers that are marking up the same product and condemning the cheaper roofing material. (What can I say I'm a skeptic when it comes to capitalism as I am one of them!)

Has anyone compared the prices between the two? There is a BIG BIG difference in price. I paid only $69.00 for a some that was 10 or 12 feet wide by I believe 50 feet. The building supplier has it in much larger sizes too if you have them order it.

I'll be very interested in their response.

My cousin used construction grade roofing liner/underlayment for her pond. Her pond is a 50 by 90 ft pond and only about 6 feet deep. She uses it for coy and other goldfish. She hasn't had a problem with the fish getting sick. She has had the pond for over 8 years. The roofing material was much much much less expensive than the pond liner. That is why she went that way.

It does not seem to have an outward effect on the fish, but she is not catching them or eating them. Thus I don't know if there are any chemical problems with the fish. Her pond has remained in balance in every way throughout the time she has had it. It also has not shown any leaks and with the roofing material you can get larger widths ( when you buy from someone doing industrial roofing ) that do not have seams.

I thought of doing that with mine originally but did not want the added expense of the liner since I thought my clay was going to be good enough. But with this summers drought and the natural seepage I get I was down about 4-5 ft over a 3 month period with no rain. Now I sort of wish I had put it in. But too late now!!! Ahhh well lessons learned.

Eric,

Thanks for the response. If it's due to the flame retardant potentially leaving a residue in the fish I can handle that as I won't be eating them anyway. When I catch the fish for sale to taxidermists I see dollars signs and not fish in a skillet!

I still have to wonder if these chemicals cannot be tempered or washed off.

I pulled out twenty 10.5 to 12 inch perch in the last few days and each one is a $10.00 dollar bill (for schools and larger orders) for taxidermy schools and bigger ones like the two close to 14 inches I took yesterday even more.

Eric and Bruce,

I just called a local building supply and they need to call their supplier and see if they can order larger pieces, but here are some sizes and thicknesses and their respective prices for reference.

100 X 20 at 45 mil is $718.00 and the 60 mil is $975.00.

I have to wonder if the only seepage in my pond is where the dike meets the ground on one side, if a piece over that dike to the bottom which is below the dike would solve the problem. Any ideas? I will also be flowing water into the pond.

Here's your link, Cecil.

http://www.pondliner.com/EPDM.htm

This lists 45ml pond liner quality EPDM for 720 dollars. That sounds pretty comparable to your roofing liner quote.

If you are looking to get rid of some of the materials in the underlayment by washing them off or soaking them, you will have a bit of work ahead of you.

( In my real life I am sort of working on these issues for similar products that we are developing )

Most of the underlayments are either a rubber based or polymer based material. In either case most of the antifungal and antimicrobial material added to the sheeting as well as the flame and fire retardant materials are integrated into the formulas and as such into the master batch of the polymers prior to making them into the end product.

What does that mean you might ask? In short they materials ( for any housing or any materials that come in contact with humans ) have to go through an EPA review. Part of the review is to issues around exposure to humans and other such critters. Some other tests that they uuse are leaching tests. The material must not give off over a certain amount of the active chemistry over a certain period of time. In the case of fire retardants, antifungal and antimicrobial materials the leach rate is measured in years of exposure not hours of soaking.

Thus in short if the material is treated with or has such chemicals in its makeup, you would not be able to wash it out in a matter of hours. It would be designed to be at most a slow release over a period of years to decades.

Now that being said, not all building materials use those materials in them. Some of the underlayments ( such as what you may be looking for around the pond liner ) do not add anything like that to the materials. It is expensive and time consuming to get the EPA approvals. they instead rely on the "Felt cloths" to do that for them. Thus some of the underlayments may be just what the doctor ordered.

As for the thought that the pond liners and the roofing material could be the same materials, I checked back through Hoovers and found that indeed some of the larger chemical manufacturers do make the pond lines and the roof underlayments. Thus like in my field and current company they may make the same product and sell it to two different applications and make a 20% margin on one product and a 75% margin onthe other. If you have a specific underlayment that you are looking to use, I would look up the MSDS sheet on that product to see what the active chemicals are in the product and what their MSDS values are for each component. From there a determination can be made as to the effect it could have on the pond, fish and eco system.

Long story short I still think if you find a manufaccturer that makes both the pond liners and roof underlayment you should be fairly set provided that the MSDS sheets check out.

Sorry for the long dissertation on this but what do you expect from a chemical process engineer.

CB1 - The chemicals on the liner may be diluted enough in larger ponds to cause less of a problem. Dilution to extremly low concentrations is sometimes acceptable in cases like yours. I question if a liner just on one side would be adequate to stop leakage. Water under pressure from depth is very persitant and will seek the path of least resistance and move in that direction. Your existing leaky situation proved that fact. Have you considered dividing the small long pond into two ponds with two liners. You are always looking for more segrated space and another small pond to hold fish. Two smaller ponds for your needs may be very useful. You could drain the pond build a wooden or similar wall in the middle install liners and refill. The wall method would eliminate the needed space/volume needed for building a dike.

Eric's long knowledgable answer is example why having numerous experienced people present on this board makes the fourm quite valuable.

Eric,

No problem at all. Keep it coming! I got an 'A' in general chemistry in college. Does that count?

Bruce, yes looks similar. I guess where I found the price disparity was in the smaller size pieces sold for water gardnes. Maybe with the larger pieces there is not as much disparity in prices?

I.E. a 45 mil piece that I used for my in ground well tank that I believe was no more than 10 by 10 was over $200.00 from a pond supply catalog.

Bill,

Thanks. Makes sense on the dilution and don't we all know too well how peristant water is! Dividing the pond is an option I never thought of.

I think that Billis right that if you put the liner in front of the area you are concerned with it will find a way to get around it. Even if you knew the exact spot of the problem, you would have to do a seamless seal between the liner and the clay in such a way that the water would not follow it and find a way to leak around it. I have seen some smaller ponds where a small rock poked a hole into the liner and as such water leaked behind it and the liner eventually bubbled out and floated to the top because the pressure was equalized.

As for cost of liners vs. that of Roofing materials, if you go through a wholesale distributor and only order a little you will not get much of a price break, but if you have someone in the industry who does a significant amount of roofing on industrial buildings you can get a great deal if they order it for you. My cousins was down around the $0.02/sq ft range.

Eric, I found the following on this site:

http://www.hgic.umd.edu/pubs/online/hg17%20pfv.pdf

"A more recent entry into the pond market, which is very similar
to butyl rubber, is EPDM. This is also a type of synthetic rubber
that is less expensive than butyl and has the same appearance and
durability. It is the thickest liner available (45 mil). It is a dark
charcoal gray or black and quite flexible and easy to install. EPDM
was originally used in the roofing industry and was manufactured
with an antifungal mineral talc coating . Some problems of fish
toxicity have been reported with earlier EPDM. The products
marketed as fish safe EPDM do not have these mineral talcs and
are very safe to use for ponds.

Sounds like the problem is the talc mineral which VanGorder mentions in his book Small Scale Aquaculture with using swimming pool liners for aquaculture. He says to scrub the liner with soap and water or soak it in a larger pond before use. Of course this would not be practical with a larger liner but it is food for thought. I don't have as much problem with talc as I do with PBDE's. Seems like I could install the liner and fill the pond and let it set for a while and potentially be O.K.

$0.02/sq ft range!

I really don't know but if you're willing to get the right answer to that question better to ask those people who has expertise in this matter to help you.All I know about
roof is the most important part of our home.