Best EPDM Liner adhesive for vertical surfaces

[Whamrick]

Hi!

I am building a pond and am struggling to find the right type of adhesive for my liner. Our mason is going to lay CMU around the base of the pond to provide the structure and then build a low brick wall (two brick widths thick) from the top of the block to about a full brick course above the water line. My plan was to use my EPDM liner on the bottom of the pond, and adhere it to the inside of the outermost brick and the inside of the CMU structure. After the interior brick course is laid, I will use a silicone (fish safe) caulk along the bottom of the interior brick course and use an epoxy sealer on the brick to create an extra barrier up to the water line.

If I can figure out how to post a photo, I will upload my wall section!

My research indicates that Firestone Bonding Adhesive may be the best product for the job, but I am struggling to find it OR if I can find it, it seems pricey. I am considering Lion Guard as a back up, but I am wondering if I could use a plain EPDM roof adhesive instead? I do not plan for the adhesive to ever be exposed to the pond water, so I cannot imagine it needs to be fish safe, and most roof adhesives are waterproof anyway!

EPDM Bonding Adhesive LG-BA10 High-Strength, (1G)

EPDM Bonding Adhesive, LionGuard LG-BA10. High-strength solvent based neoprene rubber adhesive. For EPDM Rubber Roofing. Made in USA. 1-Gallon Can. Price/Can. (flammable item; UPS Ground or Truck Shipment Only; Cannot ship to VOC restricted areas)

www.bestmaterials.com

Appreciate any advice!

Thanks!

 

[combatwombat]

Welcome. Please do post a diagram of the construction detail you're thinking. When done correctly, there should be no need to use silicone or any other sealant as the liner should do all the work. Without a photo/diagram, I struggle to picture exactly what you've described.

 

[Whamrick]

Sorry it is a little crude! But hopefully if conveys the general assembly. The red line represents the flexible liner. There will be an epoxy sealer on the inside of the brick.

 

[j.w]

@Whamrick
I can't help ya w/the adhesive but I hope your photo will help others to see what needs to be done.

 

[Mmathis]

Hello and welcome. Can’t get the pic to download. Curious as to why you don’t use a larger liner.

 

[combatwombat]

Ok, I see what you’re going for now. You’re thinking one brick course above water line? Brick is how thick? 2”? More? Not understanding why you need adhesive or silicone.

 

[Whamrick]

Hello and welcome. Can’t get the pic to download. Curious as to why you don’t use a larger liner.

Thank you! My liner is plenty large, I am trying to hide it! Is the JPG easier to read?

 

[Whamrick]

Ok, I see what you’re going for now. You’re thinking one brick course above water line? Brick is how thick? 2”? More? Not understanding why you need adhesive or silicone.

It will likely be 2-3 courses above the waterline including the rowlock, drawing not to scale! The brick is standard size, so 3-5/8 x 2-1/4 x 8 nominally. Not needing any adhesive would be a great outcome! I have a tendency to over engineer, so this forum seemed like a great place to ask!

Since we will add the rowlock last, should I drape the liner over the edge and trim it until the interior bricks are laid?

 

[combatwombat]

It will likely be 2-3 courses above the waterline including the rowlock

Got it. That is more than sufficient. No need to waterproof with anything else.

Not needing any adhesive would be a great outcome!

I'm still not sure what you are/were planning to adhere the liner to? The vertical brickwork? Not necessary. The pressure of the water pushing against the liner/brick will do that work.

Since we will add the rowlock last, should I drape the liner over the edge and trim it until the interior bricks are laid?

I would not trim the liner at all until you're ready to place the capstone/rowlock. Give yourself a good 6" of extra liner, fold it over and tuck between the two columns of brick, then place your rowlock.

Looks like the rowlock is elevated/above grade? If it were at grade, I would say drape the liner over the exterior column of brick, place the rowlock, and don't trim the liner at all until that's done and the pond is full.

 

[poconojoe]

I agree that the pressure of the water would keep the liner in place.

But, I would be way more concerned about how to stabilize or keep in place that course of brick that is submerged and sitting on top of the liner material.
I can't see it being very stable. It's not anchored to anything. It's just sitting on the liner and the back of it is against the liner.
Plus, if there's any settlement or shifting of the soil underneath, those bricks will loosen up.

I think the key is that you need to make that shelf (that the bricks are sitting on) much more shallow. Make it so that only one brick is sitting there and it is only half submerged.

I hide my liner with large stones in a similar fashion, but the shelf the stones are sitting on is very shallow and pitched slightly away from the pond. It's so shallow that only about half of the stones is submerged. Then I add more large flat stones on top of those and step them back, away from the pond.

Hope this helps.

 

[combatwombat]

But, I would be way more concerned about how to stabilize or keep in place that course of brick that is submerged and sitting on top of the liner material.
I can't see it being very stable. It's not anchored to anything. It's just sitting on the liner and the back of it is against the liner.
Plus, if there's any settlement or shifting of the soil underneath, those bricks will loosen up

Thinking you could do the base prep under the liner then place larger slabs for a base over the liner and build brick wall over that. Then with the capstone bridging both walls, I think that would be pretty stable.

 

[poconojoe]

I will add this:
Have another deeper shelf in front of that (liner hiding) shelf for plants to sit on.
So you'll have two shelves or steps. One deeper one for plants and a shallow one to hide the liner.
This is the way a lot of us do it.

 

[poconojoe]

Thinking you could do the base prep under the liner then place larger slabs for a base over the liner and build brick wall over that. Then with the capstone bridging both walls, I think that would be pretty stable.

There's still nothing for the mortar to grip onto. It won't stick to the liner. That wall will be free standing and unstable.

If you had horizontal ties between the layers of brick extending out into the ground, that would help, but the liner is behind the bricks, so you can't do that.

 

[poconojoe]

Here's how a lot of us hide our liner:

Just replace the stones with brick if you prefer that look.

 

[poconojoe]

On another note:
Anything that is in contact with the water will eventually be covered with biofilm, algae, etc.
So, you won't have a pristine brick wall emerging out of the water.

Liner, rocks, bricks, hoses, pumps, etc. become almost hidden after a while.
I have a black 1-1/2" flex PVC laying across the bottom of my pond. It's hardly noticeable. Most people would probably not even see it.