New construction - Lots of pictures or entire project - How would you seal this pond?

[SnaffiNoo]

Hi to everyone, this is my very 1st post on these, or any pond forums, so please be gentle with me

A little backstory.... I've always bee into DIY and some small scale engineering as a job, so I'm used to creating things, on-the-go so to speak.
I have a general concept in mind, and things can evolve and hopefully improve during a project, and you deal with a hopefully solve things along the way.

With that said, a few years ago, i decided i wanted a pond, and purchased a smallish pre-shaped plastic pond (digging a hole to exactly follow the form of pre shaped plastic I found was not as easy as 1st appeared) so got fed up with that, and after some consideration, as there was an area of ground that was in need of a feature, I started digging

I have a hard clay soil once you get down about a foot, then when you get down to just over 2 feet, you hit a layer of stones/ash which I believe was laid down, perhaps 100+ years ago from giant furnace works.
Getting to about 3ft down you hit the water table, and due to a wet spring in the UK it's only recently dried out to the depth I've gone down to.
It's still damp clay just over 2ft down I'd say.

Anyway, with all that history out the window, onto some photo's

26th of Feb 2024 (this year) I started digging

The following day....

A week or so later.... (yes, very muddy, with boots sinking into the mud!)

By the 5th of March, I got to this stage:

Pretty pleased with myself, as just a hour or so after work and weekends just by myself with a wheelbarrow and buckets.

A mountain of dirt building up on the other side of the garden (which is about 3x the size of what it is in this photo right now)
But that's something to worry about another day !!!

About a week later, I'd tidied things up a bit and dug in a 12" wide ledge all along the right-hand side that will be for water plants in containers eventually:

Then come Mid March, the Heavens opened in the UK and it never seemed to stop raining.
Multiple times I had 12" (1 foot) deep of water in my future pond, as that was how deep the water table was.
(at least my two plastic ducks were able to take advantage of it!)

Progress slowed a bit as it seemed to rain almost every single day for weeks and weeks and weeks.

By 24th March, the water had finally gone down enough to get more done, (plastic ducks not so happy!)
And I decided I'd dig a trench to the right hand side that I will line with shuttering and fill with concrete to give a clean strong edge.

Is subsiquently filled to about 12" with water a couple more times, thanks to UK rian, but eventyally went back down again.
So let's skip forward another 3 weeks to 14th April and I had the crazy idea of turning the corner, making it into an "L" shaped pond, and cutting in some steps:

The table and chairs I put in the for scale, as it looks smaller in photo's than in real life for some reason, so this helps:

Around 13th May, I removed (that was fun!!!) and re cemented all the triangular ending blocks as they were not totally level and I wanted them a few inches higher.
So cut them away, and all back into place, much stronger than before:

Then around 27th May, I tidied up and cemented with SBR additive cement all around the now exposed and rough edge of the shallow wall,
to smooth the edge of concrete and blend into the clay soil (lots of cutting, hammering etc) but we got it done:

Almost up to date now, so on Friday 7th June (3 days ago) I concreted in a couple of slabs, to fit (they are sitting on a little trench of concrete also)
(SBR Slurry and metal rods in the concrete to lock it al into place)

And just yesterday I put more concrete behind them on either side, and concrete on the top to build line a Concrete bridge (metal rods in the side walls)
To lock it all together (The old "that's never going to move" mentality)

So a few overview images as to where I am right now:
(and note..... My next job is the creation of the concrete retaining wall in the trench around the right hand side) as mentioned earlier.

As I said it's hard clay (almost concrete hard when bone dry)
And stones lower down all over the place.
As stones got pulled out during digging, I'd been using some SBR Slurry to paint into holes and Sharp Sand / Cement 3-1 mix to act as a filler

And I can carry on, doing this stone removal and SBR / Cement filling of holes over the entire area.

Wow........ Well done if anyone has made it this far

So, the 6 Million dollar question (and please remember be kind as this is my 1st post, and 1st pond project)
How the hell am I going to WaterProof / Seal this ?

Due to the shape evolving into an "L" design, and the steep sides in places I've pretty much ruled out the idea of a liner, which was my initial plan.

Having Looked around the Internet and thought about what seems practical I my mind I can only think of two options.
Both of which I'm 100% will be unapproved of, but hey who knows until I ask:

1: A rubberised paint, that I know you can get, and when this is really dry I can paint over the whole thing (holes patched and smoothed with cement as previously mentioned)
2: Line it with fibreglass (yes I'm sure you do not directly fibreglass onto clay soil) but in theory, as this is HARD clay, would that be feasible ?

So, I'll leave this all here and welcome your comments/views/thoughts/suggestions (hopefully not too much criticism!)

Here is a plan with rough dimensions if that helps:

 

[Mmathis]

Hello and welcome!

I can’t address your question, but wanted to say that this is going to be so nice when finished!

I’m a liner girl. We also have CLAY and a high water table (Louisiana, USA). This won’t help in your situation, but I learned that having the water level be above ground level helped with the water table issue (water gets under the liner and pushes the liner up — called a “water hippo.”). Again, only works with a liner.

 

[SnaffiNoo]

Hello and welcome!

I can’t address your question, but wanted to say that this is going to be so nice when finished!

I’m a liner girl. We also have CLAY and a high water table (Louisiana, USA). This won’t help in your situation, but I learned that having the water level be above ground level helped with the water table issue (water gets under the liner and pushes the liner up — called a “water hippo.”). Again, only works with a liner.

Thanks for the nice comments and helpful info.
Yes, I have heard about liners lifting up, I hope this is not something I need to worry about, or I can do what's needed to avoid this. I can't control nature I'm afraid

I mentioned what I thought were my only two really practical answers I'd found so far (rubber pond paint or fibreglass) but I'm aware these products would generally only be used on a pond that's been constructed from something solid/hard. Not actually onto direct soil.
But as my soil is not fluffy soft soil, but hard clay that's been undisturbed for probably a good 100 years and once dries out is pretty hard (you'd not want to hit it with your fist) then perhaps this might be an option.

As a slight follow up to all my info I've posted. I did think I could mix up some cement and SBR Additive, and simply with my hand, give all the hard clay a soft of very thin skim over to level it, and give a non messy surface for something like a paint to stick onto.

Hopefully I can look forward to some others views on how to deal with getting this waterproof over the summer months

 

[YShahar]

Welcome! I'm guessing that others will have some better advice on the various waterproofing options, but where I live (Israel) nearly all ponds are done with cement, as Aquascape-style ponds haven't really caught on here. They use standard roofing sealants, but choose those that are (supposedly) totally inert when dry.

But one other option might be ferrocement. They make everything from stock tanks to stair cases to whole houses out of the stuff, and for someone with a DIY bent, it's not all that difficult (though time-consuming). I may be going that route to hide a really ugly old metal fence in the future, as ferrocement is also good against wildfires, within reason. It's also easy to repair if any of our rather unpleasant neighbors shoots a missile through it!

Here's a video on youTube of a ferrocement pond:

Cheers!

-Yael

 

[SnaffiNoo]

Thanks for the advice and video.
Very much appreciate your thoughts and gives me additional options to consider.
I will admit, I am trying not to having to consider digging out inches more in all directions and then backfilling with concrete. Hoping very much I can avoid such a dramatic option, as I say, the soil surface is very hard and compact clay once dry, so I am hoping that once dry it will be strong enough as is.

Or course, I'm sure once the weight of water is in, there will be some flexing and settling.
So it either hard to be hard enough to withstand that, or flexible enough that it's not affected too much

 

[j.w]

@SnaffiNoo
Amazing pond build and I hope someone here can give you the best advice to seal it! I only have a liner pond here, never worked w/cement.

 

[Pablo]

Great job with all that work, it will look great. Not sure if this video series will help, but the Pond Digger gives great tutorials, this playlist is for a pond he built I think it was concrete and then he did a liner on top. There are a lot of videos in this playlist but you do not need all of them.

https://www.youtube.com/playlist?list=PLqM5Qn1K_DPy8JG3GRi8Sk-_TRYDospCD

 

[hamstermann]

Looks great, I love the stairs. I know you said you ruled out a liner, but I think I'd still go that route and use 2 liners, overlapped and sealed to each other at the bend of the L shape.

Best of luck to you! I'll enjoy watching your build.

 

[SnaffiNoo]

Looks great, I love the stairs. I know you said you ruled out a liner, but I think I'd still go that route and use 2 liners, overlapped and sealed to each other at the bend of the L shape.

Best of luck to you! I'll enjoy watching your build.

Thanks.
As I said, the design more "Evolved" rather than planned.
I had a spade and kept digging till it felt right

Yes, I did have a little look into sticking pond liner together. Seems some think it's ok, whilst others say it's a bit risky.
I guess it depends on the skill of who is installing it.
My slight other concern right now is I have some pretty sharp angles and corners, and whilst I've not actually inspected different pond liners, I get the feeling that they would rather there be very smooth and gentle curves everywhere.

thankfully no real rush, but it's good to get more ideas from people that I can investigate.
Concreting the outer wall is the next major aspect, in a few weeks time hopefully

 

[GaryMoz]

Well done so far, I like the evolving / experimenting approach.

You have a mixture of materials, each are going to expand and contract at there own rate, clay is bad enough on it's own, especially is you have any tress nearby. Personally I wouldn't trust any coating, I'm sure over time they will crack.

Having said that what are you going to use the pond for? wildlife?, if so it may not be the end of the world if it leaks a bit, just fill it back up. If for keeping fish I would go for liner.

If budget can afford it, a box welded liner, if not just a normal liner, both with a good underlay. The L shape has made it a bit more expensive for a liner, unless you join two piece.

Good luck with it

 

[GaryMoz]

Yes, I did have a little look into sticking pond liner together. Seems some think it's ok, whilst others say it's a bit risky.
I guess it depends on the skill of who is installing it.
My slight other concern right now is I have some pretty sharp angles and corners, and whilst I've not actually inspected different pond liners, I get the feeling that they would rather there be very smooth and gentle curves everywhere.

For my pond I went for a TPO liner. The liner is cut and fitted onsite, these use heat seamer and and guns to join the material. The price was about the same as welded box liner but they can do more complex shapes.

Due to rain the water table is high lifting liner, but it's not a problem the sides of the liner are anchored in at the top and bottom. When I'm ready i will seal the liner to the bottom drains and fill the pond, that will prevent the lifting.

 

[SnaffiNoo]

Thanks for your thoughts, comments and sharing your own grand project also

You have given me a few things to look into and consider.
And yes, different soil types and materials I'm wondering about how this will change over time.

With regards to what I'm wishing to put in it, At this moment, just a selection of cheap and cheerful Goldfish/Shubunkins probably.

Out of interest, is there any reason you did not consider going with Fibreglass ?
I may be talking out of my behind But when it comes to unusual shapes and to get in any out of areas, without folds and suchlike, Laying down two or 3 layers of fibreglass with a resin colour of your choice feels an interesting option.

 

[GaryMoz]

Thanks for your thoughts, comments and sharing your own grand project also

You have given me a few things to look into and consider.
And yes, different soil types and materials I'm wondering about how this will change over time.

With regards to what I'm wishing to put in it, At this moment, just a selection of cheap and cheerful Goldfish/Shubunkins probably.

Out of interest, is there any reason you did not consider going with Fibreglass ?
I may be talking out of my behind But when it comes to unusual shapes and to get in any out of areas, without folds and suchlike, Laying down two or 3 layers of fibreglass with a resin colour of your choice feels an interesting option.

Fibreglass was an option, but from what i under stand you really need smooth rendered walls and a concrete floor for fibreglass, or at least that what the contractors say they need. Also looking at the pricing it was more expensive., I could of looked at doing it myself but didn't fancy it, not 40+ m2

I think I would throw a liner in

 

[GBBUDD]

Thanks for the advice and video.
Very much appreciate your thoughts and gives me additional options to consider.
I will admit, I am trying not to having to consider digging out inches more in all directions and then backfilling with concrete. Hoping very much I can avoid such a dramatic option, as I say, the soil surface is very hard and compact clay once dry, so I am hoping that once dry it will be strong enough as is.

Or course, I'm sure once the weight of water is in, there will be some flexing and settling.
So it either hard to be hard enough to withstand that, or flexible enough that it's not affected too much

Building on hard pack is great for liners with an underlayment, however concrete by it's self even on a hard pack must have some sort of re enforcement. be it wire rebar or even concrete cloth. and to be honest with you though it is not cheap i think that is your answer . Concrete cloth is used to create storm drain swails and catch basins. it needs to be temporarily supported usually leaning onto an angle wall. Then lightly misted repetitively and eventually it hardens like regular old re enforced concrete,
will fiberglass work with what you have made yes if it's thick enough but for how long who can say.

 

[SnaffiNoo]

Building on hard pack is great for liners with an underlayment, however concrete by it's self even on a hard pack must have some sort of re enforcement. be it wire rebar or even concrete cloth. and to be honest with you though it is not cheap i think that is your answer . Concrete cloth is used to create storm drain swails and catch basins. it needs to be temporarily supported usually leaning onto an angle wall. Then lightly misted repetitively and eventually it hardens like regular old re enforced concrete,
will fiberglass work with what you have made yes if it's thick enough but for how long who can say.

Thanks for your input.
I'd never even heard of Concrete Cloth before.

Not being in the "Pond Industry" of course
I'm struggling to be able to understand what forces will be at play here from water pressing against hard compacted soil.
From day one, my intention was always, underlay and then a liner, as that's the most cost effective and seems to be well known and used way to make a garden pond, but as shown in the photo's I've sort of made it less and less practical a shape for a liner.
Not impossible of course, with shaping/cutting/joining, but certainly I've made life hard for myself!

I know such a product does not exist (as far as I know) but in my mind (imaginary product!) I wish someone made like a thick rubberised spray that you could literally spray onto any surface, and after a few hours lay down 3, 4, 5 coats and build up something like a 2mm or more flexible layer that would of course cover any surface and any shape.

Feels like such a product should exist