Finishing off the liner and edge of a BOG made with stacked landscape blocks

[Mmathis]

This should be simple to figure out -- you guys do it every day -- and do it quite well, judging from your pictures. But my DIY skills are.......
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The bog [we're getting closer every day!!!!] is going to be made with stacked landscape blocks, and I'm confused about what to do with the edge of the liner, including the extra liner. Will have capstones on top [which I was hoping to be able to "cement" to the blocks for stability] but then what of the liner?

STEPS: When we install the liner, my common sense tells me that we'll install it the same as the pond and there will be overhang which we leave alone for now. We'll then install the PVC water distribution system, then fill it with gravel, then water, and let it settle. After it settles, we'll put the capstones on top, then eventually we'll trim the liner???

• It just doesn't seem right to TRIM any liner , but at the same time, it seems like if we double it back it will be bulky under the capstone.
• I have nightmares of the liner slipping back into the bog...... if it's just the amount that's the width of the block as the extra
• then, is there any way to secure [or cement] the capstone to the top block -- to the liner.....???
• And when I say "settle," how long should that be -- days, weeks, months? -- I'm OK with "forever," except that we would eventually like it to look nice

This is what I perceive.....

HELP! Because after all the re-dos we've had to do lately, the LAST thing I want to do is screw up, install or cut the bog liner wrong........then have to pull out....... ALL .....THAT......GRAVEL ....and start over.....!

EPDM liner, BTW.

 

[Big Lou]

I'll leave the advice to the experts! Lot's of progress my friend. Continued good luck. Have fun!

 

[randythawkins]

thoughts when doing my pond liner...it should not slip back in if there is nothing pulling on it. when I did my pond I placed the liner and filled with water. the water will pull down on the liner what it pulls down and after a few weeks I assumed that it has pulled all it was going to (minus any settling which I don't expect in mine as the soil under was never disturbed). I trimmed the top, leaving some extra in case it did settle some, and then tucked it under the capstone. from the looks of your drawing, you will have many inches of extra so if some does get pulled it won't so much that the top of the liner is below water level.

For my waterfall I used construction adhesive to secure the my top 2 blocks to each other with the liner being only half way in between - not all the way like yours. I also placed some adhesive above and below the liner hoping it would provide some resistance to being pulled out and it does seem to help some (or, quite possibly, the liner is really just being pinched between the 2 blocks with the weight doing the pinching). Either way mine feels secure and not like it will just fall out.

 

[Mmathis]

thoughts when doing my pond liner...it should not slip back in if there is nothing pulling on it. when I did my pond I placed the liner and filled with water. the water will pull down on the liner what it pulls down and after a few weeks I assumed that it has pulled all it was going to (minus any settling which I don't expect in mine as the soil under was never disturbed). I trimmed the top, leaving some extra in case it did settle some, and then tucked it under the capstone. from the looks of your drawing, you will have many inches of extra so if some does get pulled it won't so much that the top of the liner is below water level.

For my waterfall I used construction adhesive to secure the my top 2 blocks to each other with the liner being only half way in between - not all the way like yours. I also placed some adhesive above and below the liner hoping it would provide some resistance to being pulled out and it does seem to help some (or, quite possibly, the liner is really just being pinched between the 2 blocks with the weight doing the pinching). Either way mine feels secure and not like it will just fall out.

That solves my problem -- thanks! I don't have to have the liner go all the way to the edge, but I can leave a gap like your pic shows.

Still wondering how long I should let the liner settle before I cap it off.

 

[randythawkins]

Still wondering how long I should let the liner settle before I cap it off.

If you have placed a lot of dirt, pack it down as much as you can. Also, when you do the liner leave some slack on the sides - don't pull it tight up the sides before securing it. Instead, pull it some just to make sure it the way you want it and then drop it back down a couple of inches. (You are just going to throw away what you trim off so, instead, let it sit loose on the inside providing extra if needed.) In your drawing you show bog rock pressing the liner against the inside of the wall. If that is the case then I would let all that extra sit down at the bottom corner folded so that if any pulls from below it will pull from under the fold (see the red line in the attached image). If it were me, I would probably also leave some extra slack on the bottom itself for the same reasons - if there is some settling in the center it will pull from the nearest slack and not *try* to pull from the corner. If you do that then you really don't have to wait for settling. Having said all of that, that is how things work in my mind. Others may have different thoughts or experiences.

 

[Mmathis]

@randythawkins -- Thanks! That's great information! Yes, if at all possible I would like to preserve the excess liner -- you never know when you'll want to expand or change things around!

We will be packing some dirt inside the bog-pit, up against the bottom and edges where the blocks slant. The area SHOULD be pretty well packed down by now, but I'll get Son in there with the dirt-tamper before we add the liner [and underlayment], just to be sure.

 

[randythawkins]

@randythawkins -- Thanks! That's great information! Yes, if at all possible I would like to preserve the excess liner -- you never know when you'll want to expand or change things around!

We will be packing some dirt inside the bog-pit, up against the bottom and edges where the blocks slant. The area SHOULD be pretty well packed down by now, but I'll get Son in there with the dirt-tamper before we add the liner [and underlayment], just to be sure.

I think you will be fine. Just don't pull everything tight - leave a bunch of excess on the inside spread out all over the place. It does not cost extra, will not hurt anything, and, as you said, it might come in handy later.