How do I get a smooth finish to concrete?

[paddypower]

I’m having a load of ready-mix delivered to form a 6” thick reinforced base for a pond measuring 14’ square and 3’ below ground level. How can I get the smoothest surface to the concrete? I thought about using something I’d seen in a hire shop, it’s a float about a metre long on an extending pole, I’d be able to reach all sides then. I’d use it after tamping. So a couple of questions, when should I float the concrete, just after pouring or wait till its setting? Is there a better way of doing of this?
regards

 

[Jasonb]

Problem with using a ball float/easy float is that the handle needs to be held quite flat, the fact your concrete is 3' below ground may give a problem.

Easier to just float the top as you place the concrete.

I would suggest that you actually cast a flat slab which can just have a tamped surface, build up your walls and then slope the surface down to a bottom drain and feed your filters through this.

See My pond

Jason

 

[paddypower]

Thanks Jason,
superb pond, real pro job. Mines not going to quite that professional, a garden pond rather than Koi. I wanted to get the slab smooth just to make final finishing simpler. just out of interest is it fibre glassed or render?
regards

 

[Jasonb]

Both The block walls were rendered and the sloping base formed with sharpsand/cement all was then direct fibreglassed.

Jason

 

[noseall]

you are best tamping the concrete regardless, it will help compact the mix and relieve any air in the concrete.

try and tamp the concrete so that you leave it as flat as possible, avoid leaving any ridges.

go have some breakfast and a cup of tea.

once firm you will be able to trowel it up. you may need to work a polyfloat over the surface first before you finally trowel.

the longer you leave the concrete the better the finish you will get. this comes at a price though and will be very hard to trowel, hence leaving the tamped finish as smooth as possible.

 

[paddypower]

OK Noseall I'll be patient before trowelling, thanks for the tip.

 

[^woody^]

A paddy that can't trowel concrete . It'll be ice to the eskimos next. lol.

Along with the other advice, if you tell the supplier that you want to be able to trowel this really smooth, then they can alter the mix to give you a head start

 

[paddypower]

Hmmm, I'm what the irish call a 'blow in' so I wasn't born with a trowel in my hand But I can lift heavey weights !! Thanks for another tip...