Collapsing pump vault - any fix?

[Lisak1]

Here's a question for those of you who are way smarter than me. We have a pondless waterfall with a pond vault and a few Aquablox in the basin. It's about 9 or 10 years old. Over time, the pressure from the rocks and gravel around the vault have caused the sides to slowly bow inward. We pull the pump in the fall (just did it today, hence the quetion!) and put it back in once it gets warm enough in the spring. But those bowing sides have turned what was once an elongated oval shape into something approaching an hourglass - the center is getting narrower and narrower. This past spring it was a real struggle to cram that pump in that space. Once it gets past the opening, it's fine. The base of the vault hasn't changed shape - just the top.

I've wondered if there was some kind of spreader we could use to slowly push those sides back in to shape. I'm not sure what that would look like or how it would work... but something that you could get in place and the put pressure from the inside to push those sides back out and then hold it there.

Am I kooky? Is this going to end with me digging all that rock out and putting in a new vault? (And by "me" I mean one of my strong boys - who will indeed tell you their mom is kooky!)

 

[brokensword]

my first thought, Lisa, was to use a jack with some sort of plates large enough to push on both sides. My gut says that even if you push it back out, it's going to collapse back in soon after the jack is removed, or over a span of time wherein the stone shifts back to being a problem. I think you need something structurally more solid to retain your vault's shape. Not sure how well it would work but you might entertain the idea of using chimney flue liner (ceramic). Or you could customize one by building a form and pouring reinforced concrete but that sounds like a lot of work to me.

My makeshift vault (made from plastic kitty litter buckets stacked) built 10 years ago is holding up well at 40" depth; how deep is your vault? I imagine the shallower the less pressure brought to bear on the vault. This spring I put in a plastic trash can to house a lotus and noticed it too is being pushed in from the rock. Course, I have like 30" diameter and don't have to move a pump in and out, so...

Just spit ballin'.

 

[Lisak1]

I'd guess it's about 3 feet deep. A jack was kind of what I had in mind... but something permanent. Which would be an issue with getting the pump in and out. I also considered leaving the pump in, but that water must freeze, right? I'd hate to lose the pump.

 

[Mmathis]

Pics might help!

 

[brokensword]

I'd guess it's about 3 feet deep. A jack was kind of what I had in mind... but something permanent. Which would be an issue with getting the pump in and out. I also considered leaving the pump in, but that water must freeze, right? I'd hate to lose the pump.

Lisa; I'm not wholly familiar with a pondless waterfall, but it would seem if your vault/basin is deep enough below the frost line, your pump could remain, no? You might have an issue though in the future should the sides continue to push in, if you ever had to rescue the pump. Were it mine, I think I'd just dig it all up and put in something sturdeir than what you have now. You might be able to leave your vertical vault pipes, dig out all the rocks and get some flue liners that would go over top your existing vault pipe, ensuring that the rock, when put back, won't push anymore. I googled and found one in stainless steel;

316L Rigid Chimney Liner (All Fuels)

316L All Fuels Rigid Liner

firesidechimneysupply.com

I found a 12" x 24" clay version; you'd need two and have to cut one and stack it. I'd probably also put something flat along two sides (or get some roof board aluminum spacers

https://www.shelllumber.com/rh-taml...MIuqun1aDy7AIViYbACh2RxQCtEAQYByABEgI44vD_BwE

so the two can't lose their alignment;

https://www.menards.com/main/building-materials/concrete-cement-masonry/construction-concrete-blocks/12-x-12-x-24-clay-modular-flue/1796602/p-1444441456439.htm

Not sure how your basin works re how water enters but you can cut flue liners to get what you need using a masonary blade.

 

[Jhn]

Depending on how far down the bowing is happening (Sounds like in the middle) you could get a scrap/piece of corrugated hdpe pipe (smooth walled on inside)to sleeve over the pump vault. Probably only need something 18” or so long. This stuff is designed to be buried in the ground.Then you would just need to remove the gravel part way down, place in this piece of pipe, jack out the pump vault.....may need to put some type of strut inside the pond vault pipe for awhile temporarily to get the pipe to hold back to its original shape.

Then the hdpe pipe should keep the pressure of the water and gravel from pushing in your pond vault. Hopefully your pond vault is designed to be pulling in water down lower at the bottom than where the pipe would be sleeved is going.

 

[Lisak1]

@Mmathis - you are so right! As I was working on this project yesterday I thought "I should grab my phone and get a picture". Phone was in the house - I was outside - hands were dirty - feet were dirty... ugh! I'll see if I can get up the gumption to go unbury it again and get a picture today.

@brokensword - after looking at the specs on this, I think this is only two feet deep. That may be deep enough to leave the pump in, and one of these years I may just be forced to do exactly that. We can't keep this feature running during the winter because ice forms on the gravel at the top very quickly and then we have an ice skating rink on our patio! But leaving the pump in a basin full of very cold but not frozen water shouldn't hurt anything.

@Jhn The bowing is right at the opening. I totally get where you're going with that solution and it makes sense. However the actual basin isn't much bigger than the vault so I don't think we could get anything in there to go around the vault. We built this in a really tight spot that was created when we installed a new patio, so it's pretty landlocked as far as size. And I'm not even sure this thing will bend back to the correct shape without some pressure from the inside.

My husband said "I KNOW! Let's just FILL THE VAULT WITH STONES!" And then what... dig them out again in the spring? This is why I'm the idea person around here. haha! I mean, in theory, yes, but from a practical point of view, no. His other idea is to contact Aquascape - and while I'm 100% positive they will stand behind the product and replace it, that still means digging the old vault out.

Part of this may be caused by a construction error on our part, too. We have the two biggest rocks in this whole feature sitting right on top of the basin. I'm sure that's putting a lot of pressure on those rocks underneath and the only "give" is the sides of the vault. Although that wouldn't really account for why it's bowing on both sides... But anyway, if we were to remove the old vault that will mean moving that two big boulders, which would not be fun. Doable, but not enjoyable.

This is the vault we have. Looks real sturdy, no? Well it ain't. The lid doesn't even fit anymore - it just sits on top, keeping rocks from falling in. And based on the orientation of ours in the basin, I think this has changed since we installed ours - I think our snorkel is coming out of one of the narrow sides.

Here's a good picture of the pondless waterfall - ignore the fact the patio is flooded. I took this after we had a heavy rainfall that flooded the whole back yard. The actual basin is smaller than it looks - the river rock extends past it on either side by a good amount.

 

[BKHpondcritters]

I have no idea how to fix your problem, but I just wanted to say that's a really pretty pondless!

 

[Jhn]

@Lisak1 Is the wide side collapsing in? If so my thoughts are getting some thick flat pieces of some inert material like acrylic sheets, jacking the walls back out using the acrylic sheets cut to fit on either side of the jack. Once walls are relatively where you want them add something-to hold the walls in place ie strutting the sides at either end of the flat pieces of acrylic to keep it from collapsing back in once the jack is removed. Ideally the flat pieces would be thick enough say like a 1/2”-1” thick to add strength to the sides, basically like building a trench box in the construction trade. Of course you would need enough room in between the struts to get in there to remove the pump when needed.

Nice looking falls and basin, I like how it comes down right next to your patio.

 

[Lisak1]

Thanks for the compliments - we love this feature. It was the first one my son built for us when he was 19. Now he cringes when he looks at it - too many small boulders! But it was a really challenging project for a first timer - we cut out the retaining wall, and then had to figure out how to transition from cut timber wall to rock waterfall... so stacked boulders seemed to be the best solution. Also those rocks are sentimental to me. When we first moved into our house and my kids learned how much I loved rocks, they started collecting them for me. Our subdivision was brand new, so every time they started digging for a new foundation the kids would scour the construction site looking for only the "best rocks" for mom. Over the years I used them to border my gardens. When it was time to re-do the backyard and make some big changes, we pulled up all those rock borders and put the rocks in a big pile, and that's what we used to build the waterfall. The two largest ones in the front were quite the project to haul home - they worked for DAYS on those, enlisting the help of all the neighborhood kids and coming up with some pretty creative methods for moving heavy boulders! So those are my "mom gems". They remind me of those very sweet kids who were always on the look out for a pretty rock for their mom! There are some real beauties in that pile!

Anyway - here's what I'm dealing with. You can see from the size of the lid just how much this thing has distorted at the opening. Some kind of brace makes sense, but then how would I get the pump in and out? Unless I put the pump in, then braced it, then remove the brace, remove the pump, and replace the brace in the fall. (Ignore all my pine needles - my white pines are really dropping needles this year!)

 

[clark kent]

If you are comfortable mixing concrete (or know someone who is), you could make a concrete "collar" around the collapsed area of the vault.

Remove enough rocks to completely expose the collapsed portion of the vault.

Fill the vault with rocks to press it back into its normal shape. You will be removing these later.

Create a form around the vault a few inches larger than the vault, to create a void area around the vault about a couple of inches thick, using something fairly rigid but bendable, like PVC roof flashing material. Use duct tape and rocks as necessary to hold the form in place. Note that concrete is a bit heavy, so whatever you use to hold the vault and the form in shape needs to be sturdy enough to support and contain the wet concrete until it hardens. Some fine gravel in the bottom of the form will prevent the concrete from oozing out the bottom.

Fill the void area you created between the outside of the vault and the form with concrete. One forty pound bag of ready mix should be enough. It should be mixed to a consistency that will allow it to be poured into the void area, but no looser than that.

Once the concrete hardens in about 24 hours, you can remove the rocks from inside the vault. Removing the outer form is not necessary unless you want to. The walls of the vault may eventually spring back into their compressed shape some, but the concrete will prevent the rocks outside from collapsing the vault again. The walls of the vault should be flexible enough to allow you press them out enough to remove or replace the pump.

 

[GBBUDD]

My gut says that even if you push it back out, it's going to collapse back in soon

agreed to a point

ut that water must freeze, right? I'd hate to lose the pump.

if your pump in at a depth of 30" i doubt you get that much ice 24 is extreme maybe in il you might but place an air stone next to the pump and you know what i mean by that not just an aquarium pump.

What i would look at is something i can not find for you but i know they exists. and that is a product aquascape has made for just this reaso. They have basically a aquablocks panel that is heavy duty and is made to be placed on the top of aquablocks before all the stone is placed.
AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH H O L D T HE PHONE

If my memory serves me correctly you have left over aqua blocks . Use the panels to re support the sides and the top of your vault. if you don't want to pull back the stone it should sill work inside the vault id place two or three on the sides and two of the attached or make your own and cover that with an aqua block panel or two i would also use a couple to keep the sides from coming in any further against the newly installed side pieces box it right up take some rock out so you can regain what you have lost the aquablock pannels should do the job

AquascapePRO - AquaBlox - PANEL B W/ HOLE - 94013

AquascapePRO - AquaBlox - PANEL B W/ HOLE - Quantity of 1 Panel. Item # 94013 Replacement Panel B with hole - for

www.123ponds.com

 

[Lisak1]

Creating space around the vault makes sense... concrete may not be the medium I would choose to work in, but you've set my brain on a path!

@GBBUDD - I've never seen that product before! That's intriguing... and we do indeed have several leftover Aquablox. Good memory! I wonder if the small one would fit down on top of the vault to create that void space around the vault @clark kent got me thinking about? I'll check the specs. I may still have to remove some river rock, but it wouldn't require taking the whole thing apart...

Thanks for the brainstorming! You've given me some things to think about!

 

[GBBUDD]

Aquablox don't have to be as made and designed . I have altered them to the desired size I wanted and the used zip ties to hold them together. The more pressure you feel you might have will determine how often and how thick the zip ties need to be .

 

[frogbath]

Maybe clear out around the top and just bury a small wooden frame around it to take some of the pressure off the top of the vault. With the picture it's not as bad as I was imagining. Curious to hear how it works out!