I read somewhere that roofing liner is not good for a pond. It has chemicals in it that poisons the water.

Not good for pond life from what i remember.. maybe an algaecide?
But if you search on the net.. i looks like many people use it just fine.

Here we go again!
There is nothing wrong with using EPDM roofing membrane as pond liner.
Thousands of pond owners will vouch for it's use.

Sheryl, I dare say you have checked with the local roofing companies in the Barrie area, to see if they have EPDM
roofing membrane/pond liner in stock.

At this time of year the pond outfitters/garden centres, usually drop their prices a bit, to get rid of the stock they have. You could check around.

"Horton"

I too have used EPDM roofing membrane to line my pond. That was two years ago and no problems so far

I also used old carpet as a cushion for the liner. If you're looking to save dollars then maybe that will work for you. I did a little dumpster diving at the carpet stores (if they sell it they usually install it, & they have to bring the remnants back somewhere) because the professional carpet installers usually do a nice job of neatly rolling-up the remnants. That makes it easier for a DIYer like me to transport it.

For the liner, I would call a building materials supplier that uses the name "wholesaler" in their name. All the ones around here will sell to homeowners.

Oops! Thanks Horton and Pondbucket. I don't want to be passing on wrong information.

I know it has been a very long time since anyone has posted on this subject but hope someone will answer.
I have the opportunity to get for free up to half a million square feet of EPDM roofing and was wondering if anyone still thinks it is safe to use for fish? I want to use it to make long narrow trough like ponds for aquaculture connected to our greenhouse to grow food fish in. I would really appreciate any input from any point of view.
Thanks
Brad

In Phoenix, 3 million people, I've only been able to find one roofing company that sells EPDM. So not too easy to find. I think next time I'll look into buying a whole roll direct from a distributor.

Brad, define "safe". Years ago I found the test Firestone did to deem their pond liner safe. They made a temp pond and put in 6 goldfish. I think they waited 2 weeks and the goldfish were still alive so the liner was deemed "safe". It's not like there's some regulation they have to follow. So the safe door swings both ways. IMO the safe pond liner wasn't really proven to be safe any more than roofing liner is proven unsafe.

The unsafe thing for roofing liner came from claims of it being resistive to algae growth. People jumped to the conclusion that a poison was added to the liner. But the anti algae thing was more of a made up claim from the marketing department based on the normal properties of EPDM. It's like saying glass is resistive to algae growth. It is, many kinds of algae have a hard time adhering, but some will.

If a manufacturer did add a poison to the liner there would be a butt load of regulations that would come into play. EPA, building code, local. Water runs off would be in the ground, water supplies, streams, lakes. People are kind of sensitive to that kind of crap.

I like to believe data more than opinion but for what it's worth I'd eat fish grown in a EPDM lined pond. If I was invited for dinner I'd be much more concerned about things you added to the pond, the food you fed the fish, stuff in the water supply, stuff blown into the pond from your neighbors yard. But that's the world. Make a huge deal over the little things and ignore the real dangers.

Is roofing membrane underlayment or rolls of epdm?

EPDM is a roofing membrane. There are several forms. The kind used in ponds comes from the factory in a roll. Retailers cut the requested size off the roll and fold it.

So do they have it like at LOWES? Maybe i am not asking for the right stuff. Is it actually called roofing membrane?

I've never seen it at Lowes or any big box store. But stores vary greatly in what they carry. In the roofing department I have seen uncured EPDM and small widths of adhesived backed EPDM, not useful for ponds. In the pond section I've seen all kinds of materials sold as liner.

Roofing membrane is a general term describing several materials. EPDM is a roofing membrane, but not all roofing membranes are EPDM. Flour is a white powder, but not all white powders are flour. Don't know any more ways to say it.

If you're asking how to find EPDM I suggest calling roof supplier out of the yellow pages and asking if they carry EPDM. If yes, find out the widest available. If 10' or better it's probably what you're after and you can ask more questions to confirm.

I have found rolls of cut to length EPDM in the pond dept at Lowes and purchased EPDM at Menards. Ask the clerk to check their catalog. They often sell items they don't stock that way on special order. Some local Lowes stopped carrying it because it was too slow to sell. This is not a particularly big town.

A contractor's supply store might be a good source. I have seen ads that offered it.

What Horton said... I bought my 45 mil Firestone EPDM liner from a Seattle roofing supply place in 2004 and have had no adverse effects on plants or fish. I paid 38 cents/sqft back then, and "Pond Liner" was twice the price.

I did not put fish or plants in for a couple months just to let the pond settle in, but I think even that was an over abundance of caution.

Dave
check out my pond at photobucket.com/albums/v143/finnpond

Here are the facts that the largest manufacturer of liner in the US gave me. There is no difference in the formula, materials used to make the two liners and it is made on the same equipment. The only differences between the two is that the equipment is cleaned before making pond liner and care is taken not to contaminate the liner. They then test the liner to make sure that nothing has gotten on it to effect aquatic life. Are you ever going to have a problem if you use roofing liner for pond liner? The odds are pretty low that you would but it does happen. The largest pond company in the US for years sold liner for ponds that was not tested. Then they sold liner from there only manufacturer that did have a problem and there was a lot of dead aquatic life suddenly. There was lawsuits and they sent out letter saying that all liner in the future would be tested.
Yes the pricing for roofing liner is cheaper. It is not cheaper because the manufacturer wants to make more money on it but because the costs to make it are higher.
If you are going to have a problem you will have the problem very quickly. If you want to use roofing liner do so knowing that there is a very small chance that you could have a problem.
Mike

"It is not cheaper because the manufacturer wants to make more money on it but because the costs to make it are higher."

LOL I have no problem with companies getting as much money as they legally can, I'm a capitalist. But them saying that is pretty funny.

I've seen the same talc on pond liners as I've seen on roofing liner. Maybe they cleaned the talc off the pond liner and then put more on afterward? Maybe. I don't see why since the talc is only needed before the EPDM cures.

If they do clean the pond liners at all it would be a bit amazing to me that the cleaning cost requires the price to be doubled. I'm a capitalist, but that doesn't mean I believe what other capitalists say. To the contrary.

Dave. I just spent a considerable amount of time looking at your photos. Your pond and landscaping are absolutely gorgeous! Very well done.

I'm your southern neighbor down here in Oregon. Thanks so much for posting the pics.

The reason a person will not find black rubber, single-ply, roofing (membrane)stocked in Arizona is simply because it is black, and, it's Arizona.

Architects and building engineers no longer design with the intent of putting BLACK roofs on buildings in Arizona. Quite to the contrary, they usually specify white "cool roofs" on their buildings in AZ, TPOs (thermoplastic polyolefin) and the like.

I've not had any problems using EPDM (ethylene propylene diene monomer)"rubber roofing", 45-mil, as a pond liner; my water garden includes an aquatic environment with fish.

The precautions others have written about are prudent, good measures to undertake, but really, don't sweat the small stuff.

pondbucket, We're at the same latitude as S CA, NM, OK, AR, SC. Most of TX, LA, MS, AL, GA and FL are at a lower latitude. We're just above sea level, so no closer to the sun than most places. Black gets hotter because it absorbs more light than white, color has nothing to do with ambient heat.

If you take a gander at Google satellite map for Phoenix and say Rochester NY you'll see the colors of roofs are pretty much the same. When white is used here it's applied different ways like stone, acrylic elastomeric coating made specifically for EPDM, and EPDM has an option of coming with a white coating. The white coated EPDM is just as hard to find here.

Quite to the contrary Architects here design buildings all the time with dark roofs. It's only in a relatively small number of flat roofs hidden from view that white is an option.

So thanks for your opinion on why EPDM is hard to find here...but that ain't it.

Nativefish: One caution. While epdm is safe for pondliners, You are asking about using it for aquaculture. There are various formulations of EPDM but not all are certified as "Food safe". You may want to google "food safe epdm" for sources.

Here is a link that might be useful: examples of various EPDM specifications...

Food safe testing is done for food in contact with EPDM. I've never seen any FDA testing for EPDM used in aquaculture. And currently there is no FDA requirement for the type of material used in raising fish for food.

I've gotten into a couple of roof liner vs fish safe threads in different forums recently and thought I'd pull together what I've learned into a EPDM - Fish Safe vs Roofing Liner web page. I know it certainly won't change the minds of people who believe myths but will reduce the time I spend in these threads.

"We're at the same latitude as S CA, NM, OK, AR, SC. Most of TX, LA, MS, AL, GA and FL are at a lower latitude. We're just above sea level, so no closer to the sun than most places. Black gets hotter because it absorbs more light than white, color has nothing to do with ambient heat."

Waterbug_guy, sorry to be late (and argumentative)... You said "ambient heat" but I would say color has everything to do with it depending on the reflectiveness in the near infrared, non-visible portion of the solar spectrum.

"If you take a gander at Google satellite map for Phoenix and say Rochester NY you'll see the colors of roofs are pretty much the same. When white is used here it's applied different ways like stone, acrylic elastomeric coating made specifically for EPDM, and EPDM has an option of coming with a white coating. The white coated EPDM is just as hard to find here."

I say, 'okay' then you know why it is more expensive (additional coating), and, see below.

"Quite to the contrary Architects here design buildings all the time with dark roofs. It's only in a relatively small number of flat roofs hidden from view that white is an option."

Not exactly. I don't agree with your comparable analysis with other locales. You said those black roofs get extra attention by architects in AZ, and you're right... Therefore, Shop at HD in Phoenix, no EPDM (because it is largely black rubber- yes, you can specify other additional coatings, single membranes or flat roof mateirals but they're not considered Do-It-Yourself, nor are membrane roofs like TPOs or Durbigum ; shop at HD in Chicago metro and no problem finding EPDM.

"It's only in a relatively small number of flat roofs hidden from view that white is an option."

Yes, you've solved your own riddle. White roofs are highly reflective, so much so that they could possibly be a problem if held in full public/pedestrian view... fortunately, most low-slope roofs aren't viewable from the ground where they'd cause a problem.

"Ambient heat" is not a regular factor in measuring a roofs characteristics. Solar Reflectance, as you accurately point out, and Thermal Emittance are the measures that concern architects and engineers. The latter relies on other factors besides the coating, like insulation, I know - I'm an architect and engineer that inspects facilities nationwide.

Although rubber is about the easiest installation for a DIY'er on a low-slope roof, you're not finding black EPDM rubber roofing in Arizona because it is a poor choice(doing the cost analysis thing) for solar relectance, and, it makes the job of thermal emittance more difficult.

If someone wants to find EPDM (rubber roof membrane) in the south, special order it or drive to someplace northern to find it stocked.

As you quite candidly point out, it's used but it takes more work to apply it in Arizona... (when using it for roofs not water gardens).

Just another 2 cents.

I know all the sites say not to use roofing liner, but like you I wanted a pond at a reasonable price and had an opportunity to purchase some roofing liner that was left over from a roofing job. It has been in the ground for 5 years now and I haven't ever had a problem using it. I have lots of goldfish and they have spawned every year. I also have lots of wildlife living in it such as frogs, tadpoles, dragonflies, etc. Don't know about Koi as I don't have any. Those of us who aren't rich can enjoy a pond at a reasonable price. I love the DIY projects and have learnt how to maintain a pond without all the expensive equipment.