Building a pond wall question .

Cuchilo

Prize winning member X2
Location
London
I have an existing pond dug into the ground with another raised pond that water falls into it . The raised pond is a large fibre glass container ( old boat ) and that holds its own water .
I want to raise the level of the lower pond so i have one large pond so plan to build a wall around the lot , drop in a new pond liner and fill with water .
The area of the buried pond is about 2.4m x 2.4m and i want to raise the level by around 1m .
Given that the pond is already there footings for a wall is my first issue . The next is the amount of water i'm trying to contain .
Any wall experts have any bright ideas ?
I was thinking along these lines and then fill with cement .

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Salar

Über Member
Location
Somewhere
A single skin of blockwork won't hold back a one metre head of water. You'll need a properly designed retaining wall to resist the water pressure, which won't come cheap.

Thinking out of the box, what about a ground standing swimming pool, double lined with a decorative wall of some sort set back a 100mm or so, built around it, but not taking any water pressure. You could fill the gap with loose soil.
 

meta lon

Guru
There are ways to calculate..
I'd think you need a wall about 300 mm thick with re-enforced posts or piers.

Alternatively a sleeper wall ? With sunken oak posts
 

welsh dragon

a permanent vacancy now exists
We did the same thing years ago. We had a small pond dug into the ground and wanted to make it bigger and deeper. We also used breeze blocks like the ones in your picture. We set them into concrete, and put concrete and some re-bar down as well. When it was dry, we used a butyl liner and topped it off with slabs on top. We didn't have any problems with the breeze blocks at all. It worked well, was solid. We could sit on the edge of the pond without any problems.

We finished it off by rendering the outside of the breezeblocks.
 

Salar

Über Member
Location
Somewhere
A single skin wall say 100mm thick or so would in theory, if you put numbers to it (structural calculations) fail laterally on the bed joints, although being only 2.4mx 2.4m on plan , there would be some two way span effect with the corners also contributing to the strength of the wall.

Using hollow core blocks with properly designed vertical reinforcement is another option.
 
OP
Cuchilo

Cuchilo

Prize winning member X2
Location
London
We did the same thing years ago. We had a small pond dug into the ground and wanted to make it bigger and deeper. We also used breeze blocks like the ones in your picture. We set them into concrete, and put concrete and some re-bar down as well. When it was dry, we used a butyl liner and topped it off with slabs on top. We didn't have any problems with the breeze blocks at all. It worked well, was solid. We could sit on the edge of the pond without any problems.

We finished it off by rendering the outside of the breezeblocks.
Like the re-bar idea , The pond is stepped so once past the first 300mm i'll be away from the old liner . Thinking more about it , that last step in the pond may be enough for a footing ? It has had water compacting it for the last 15 years and the wall is more retaining than taking any weight .
 

welsh dragon

a permanent vacancy now exists
Like the re-bar idea , The pond is stepped so once past the first 300mm i'll be away from the old liner . Thinking more about it , that last step in the pond may be enough for a footing ? It has had water compacting it for the last 15 years and the wall is more retaining than taking any weight .

Sounds like that would work. Good luck with it, and i would love to see photos if you decide to go ahead with it.
 

Heltor Chasca

Out-Riding the Black Dog
[QUOTE 5290097, member: 9609"]I went dam shape in case there was too much frog activity
View attachment 416307[/QUOTE]

STRONG. Likeable too.
 
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