Concrete pond construction - Any additional requirements?

[dig dug dan]

I am in the process of constructing a 4m x 2m x 750mm deep concrete pond
I have dug the hole(he pond is sunk into the ground entirely), laid a concrete slab using gen3 and reinforcing mesh), have used hollow concrete blocks for the sides, 3 high,and will cap of with one course of brick. By the time the slabs are laid round, this should bring it up to the 750mm.
I plan to use a render in the walls and floor, mixed with pva. Then give two coats of primer, and two coats of "black jack", as used for tanking.
Do i need to do anything else to ensure it is water tight? someone suggested adding plastic fibres to the render, but I cannot seem to get hold of them anyway. IS this really necessary?
Is my construction so far useless?
Incidentally, The first course of blocks have a steel rod running horizontally all round, and every block has a steel rod vertically, attached to the concrete base for strength.

Any advice welcome



Edited By dig dug dan on 1169405459

[clarkey]

hi there i was in a fibreglass roofing supplier a couple of months ago and they where supplying fibreglass resin kits for ponds .Not sure if it i might be worth looking in to..
Gavin

[lutonlagerlout]

i built a circular pond in my old house similar to this 10 years ago dan but i used engineering bricks,
when i first filled it with water (took a day) i came home from work and it was empty
so i rendered the inside with 3:1 render mixed with waterproofer and that did the job
you need to centaprufe it before you render it and remember to throw some sand on to the black jack when it is still sticky as a key for the render
i think you have to leave it a while before you stock it due to the alkaline nature of cement (a year i think)
much better than liners though i hate them
cheers LLL

[dig dug dan]

I was going to black jack on top of the render.the render goes on to the block work. its basically a bitumen based paint.
what is centraprufe? The blocks are 200mm deep by the way, so its a chunky wall.
by the sounds of what you did, your render on its own did the trick, so hopefully my extra protection from the paint should do the trick!

[lutonlagerlout]

centraprufe is a trade name of black jack,good luck dan!
LLL

[Ted]

You can get fibres from PICS (www.picsuk.com) or from Creative Impressions (www.creative-impressions.com). Your local builder's merchants should be able to get them too though.

They are about £5 a bag; a bag should do your pond easily.

But for them to work effectively you have to knock you render up with a drill or in a mixer with an agitator (a Belle mixer does not have an agitator). If you mix the gear in a typical builder's mixer (ie, a Belle) it is practically impossible to get the fibres to disperse evenly as it does not agitate the gear.

Some times the fibres are visible on the surface but you can burn them off with a lighter.

They are good IMO and add a lot of strength.

[lutonlagerlout]

but you can burn them off with a lighter.

i use this paving mix for any oversite that we do ,they reckon its stronger than rebar
i like the hi-tech solution ted, lol
regards LLL

[Dave_L]

So when can we come over for a swim? :p