Spray foam barrier

[Big Lou]

Thinking of creating a underwater barrier using pond spray foam. The barrier is needed to prevent egg size rock from falling to the bottom. After the foam cures th barrier will be under water. The barrier will be 1 to 3 feet long and about 3 to 4 inches wide. This is a new project on aged but super clean edpm.

Thanks

 

[addy1]

Make sure it is dry and you might want to rough up the epdm a bit with some sand paper. That should work.

 

[DeepWater]

I wonder if you could alternatively use roofing caulk to glue down an edge row of larger egg stones.

I made a similar underwater barrier, but instead of glue, made another shelf about 6" wide, 6" deep, below the egg rocks and then put a stack of small boulders to hold it all - no glue or foam. The bottom of the shelf is angled about 20 degrees inward to keep the boulders from sliding off. (this pic is through an inch of ice cover!)

 

[Meyer Jordan]

Foam is a terrible choice as an adhesive.

 

[Waterbug]

Spray foam is closed cell, very buoyant. I wouldn't be surprised if it didn't stay put.

 

[Big Lou]

A second shelf cannot be constructed so some type of adhesive must be used. The pond is sloped enough to cause the rocks to slide to the bottom. I do have rocks about double the size that could be glued in place. All I need to know is the name of the recommended adhesive. As always, thank you for the best information.

Btw, health issues have caused me to greatly slow down my pond activity. My son or a hired person will do this work. A tip, do not fall down stairs. The result is no fun. Especially falling three separate times. One encouraging outcome is I now have a very safe procedure for walking up an down stairs.

Looking forward to your response.

 

[Meyer Jordan]

I am not aware of any adhesive that is designed for underwater use that would support the weight of rocks on a slope. Someone, somewhere probably offers such a product, but it may not be safe to use in a pond, very expensive and/or only available in large quantities.

 

[Waterbug]

Glued to liner might cause rocks to still fall...taking the liner with it. If you mortar rock (or even loose) from the bottom up the slope to where you want the shelf it will stop the shelf from sliding. The rock bracing can be very thin.

Easier, bullet proof.

 

[Big Lou]

Thank you all. We may have to place much, much larger stones on the slope to prevent the rocks from sliding. This has worked in the past.

 

[Big Lou]

Here is weird humor. You see our local temp is presently 81. This morning the temp was 42! Still have brisk winds.

 

[Lisak1]

I was going to suggest the same - build a rock wall from the bottom with larger rocks to support your smaller rocks at the top edge. Much better than trying to glue to your liner. As waterbug said, I'd be afraid the whole thing would slide and take your liner down with it!

Good to see you @Big Lou - take it easy on the stairs!