Expansion joint in block wall to be used in a pond?

[will84]

I am currently in the process of building a forty foot pond in the shape of half a rectangle. The re-enforced concrete base is in, but my concern is whether to put an expansion joint in the concrete block work? As a brickie I know they should put in every 6metres and two of the longest sides are getting on for nearly ten metres. I don't want the blockwork cracking and cracking the render.
I am rendering the blockwork with sand cement and lime then sealing with G4 pond sealer.
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[HERTS P&D]

Join the forum below:

http://www.koiforum.co.uk/index.php

Andy

PS Don't G4 it, have if fibre glassed.

 

[will84]

Join the forum below:

http://www.koiforum.co.uk/index.php

Andy

PS Don't G4 it, have if fibre glassed.

Isn't that quite expensive?

 

[r896neo]

I'm intrigued as to what constitutes half a rectangle? is it not still a rectangle?

On a more useful note its a hard one to answer. By using render and g4 you are relying on the condition of the render to form your waterproofing and if it cracks you will get leaks.

If its all on a reinforced raft i'd be tempted to forget the expansion joints and hope for the best as i'm not sure how you would detail them.

Expanded metal over the joint would probably work at keeping the cracks away.

Fibre glassing would take away all your concerns but is very spendy.


In other news i recently did a small 3x1.5m pond and didn't render the blocks but used KA tanking slurry which was brush applied to bare blocks.

I honestly didn't really believe it would work but its not leaked at all in 6 months. and worked out much easier and than rendering and then g4 on top. probably a bit cheaper too.

 

[will84]

I'm intrigued as to what constitutes half a rectangle? is it not still a rectangle?

On a more useful note its a hard one to answer. By using render and g4 you are relying on the condition of the render to form your waterproofing and if it cracks you will get leaks.

In other news i recently did a small 3x1.5m pond and didn't render the blocks but used KA tanking slurry which was brush applied to bare blocks.

I honestly didn't really believe it would work but its not leaked at all in 6 months. and worked out much easier and than rendering and then g4 on top. probably a bit cheaper too.

It's like the shape of a capital E but without the middle bit.
That's why I was going to use lime in the render to allow a bit of movement and hopefully avoid cracks.

What is KA tanking slurry? I've never heard of it

 

[will84]

I'm intrigued as to what constitutes half a rectangle? is it not still a rectangle?

On a more useful note its a hard one to answer. By using render and g4 you are relying on the condition of the render to form your waterproofing and if it cracks you will get leaks.

In other news i recently did a small 3x1.5m pond and didn't render the blocks but used KA tanking slurry which was brush applied to bare blocks.

I honestly didn't really believe it would work but its not leaked at all in 6 months. and worked out much easier and than rendering and then g4 on top. probably a bit cheaper too.

It's like the shape of a capital E but without the middle bit.
That's why I was going to use lime in the render to allow a bit of movement and hopefully avoid cracks.

What is KA tanking slurry? I've never heard of it

 

[r896neo]

google it. there are various alternatives but as far as i can tell its essentially a chemical plaster that crystalizes the structure of the masonary and stops water movement. I'm not really sure how it works exactly but it did for me.