[CDave]

My neighbour had a really big hen ouse and I can use it to collect rainwater into an IBC tank that I have. My neigbour wants me to stand it on a concrete base cause he doesnt want  to take a chance on it leaning against his shed. Judging by some IBC tanks on our site that are leaning quite a bit - I can understand his concerns.

I've been given a mould to hold the concrete by someone else that has made a base. I want to save as much time and effort (and cash) as possible. I can remember my dad making a concrete wall 24" by 28ft. In his mould he chucked in all kinds of metal pipe and a ton of broken bricks and bits on concrete. There are loads of broken bricks on our site and I'd like to use some. But how many can I put in the mould without it weakening the concrete?  I wouldn't use whole bricks and I gues that I'd have to leave some gaps to allow the concrete to surround the bricks.

Failing that - any other ideas for a really safe/sound base for an IBC?

Thanks in advance. Dave

[RichardA]

both of my IBC are on paving slabs and both are full and have been  fine for over a year.
Any inclusion such as broken bricks will weaken a concrete mix and the thinner the concrete slab the more it is weakened.
R

[Paul Plots]

I'm no expert but if you dug down a little (same dimensions as the mould) and filled in with broken brick / rubble then put the mould on the top you should find your concrete slab sits firmly.

You can get bags of ready mix concrete from most DIY places and they tell you how many cubic what's-its they make. It should be easy enough to work out how much you need.

The rubble base should mean the depth of concrete can be reduced as it'll have something firm to sit on and bind to.

Well.... that's what I'd do I think. 

[arugula]

I'd be concerned that if your hardcore (rubble) is not compacted sufficiently - either extremely thoroughly with a sledgehammer but ideally with a whacker plate - it would seriously act to weaken any concrete that you do lay on top of it. Also, as RichardA says, if you make the concrete layer too thin, it won't last at all.

What are the dimensions of the "mould" you have been given? I presume this is just a shuttering box...

[CDave]

Thanks for your replies. The mould - or shutter  I'm no builder but essentially its a box to support and contain the concrete is 1.2m x 1m x (about) 70cm high. I was speaking with the guy that made it up - he gets it level. digs a bit out of the inside, puts compacted bricks on bottom the uses a very wet concrete mix that essentailly surrounds the bits of brick. He kept adding bits of brick and "watery" concrete till his mould was filled level. Tops the concrete off to make a nice finsh and then it dries out. Hes left with a substantial bock that his IBC fits onto. It is of sufficient height to get a watering can under the tap. I'm going to do the same - I'll try to post pics when its done.Dave   

[Paul Plots]

That's a pretty deep block but makes sense to have the tank high enough to get a can under the tap.

If it worked for the other chap it'll hopefully work for you...... and last too (fingers crossed).
Good luck

[Kleftiwallah]

Why not try the idea from "The Victorian Farm" when they built the pig sty?   They set empty wine bottles in the cement and capped them off with more cement to stop the piggies feet getting cold from the ground - good insullation.

Cheers,   Tony.

[savbo]

just a thought - do your allotment site rules allow concrete foundations? Just cos someone else has done it doesn;t necessarily mean you'll get away with it, so worth checking before doing all that work. Our site doesn't allow them so I had to make by greenhouse base from blocks set on sand....

sav

[Paul Plots]

just a thought - do your allotment site rules allow concrete foundations? Just cos someone else has done it doesn;t necessarily mean you'll get away with it, so worth checking before doing all that work. Our site doesn't allow them so I had to make by greenhouse base from blocks set on sand....

sav

Good point. 

[CDave]

just a thought - do your allotment site rules allow concrete foundations? Just cos someone else has done it doesn;t necessarily mean you'll get away with it, so worth checking before doing all that work. Our site doesn't allow them so I had to make by greenhouse base from blocks set on sand....

sav

Good point. We are allowed and Ill be using up some of the trillions of old bricks that we have on the site - its next to a former NCB Colliery. Will try to get some pics at weekend - provided everything isn't covered by snow 

[bravemurphy]

try not to get the aggregate in small bags it will cost you a fortune.

Best bet is a builders merchant and get a tonne bag of what is called all in, mix that 6 buckets to 1 bucket of cement and that should be ok.

concrete too wet is much weaker ( but easier to pour)

May be better to dig out to solidish ground put a layer of bricks then some scalpings on them about 4 inches and give i a good whack with a whacker.

[CDave]

Is done. I'll try to upload a picture next week - Im off work  (sorry - couldn't resist saying that). Thanks for all the advice - much appreciated.