When you come to the point where it is time to pour the concrete base, it is also time to reflect for a moment to make sure everything is ready.
The floor of the excavation is compacted or shaped and then compacted.
Reinforcing rods are in place to support the walls that will be built.
Trenches have been dug for the bottom drains and the pipe work to the bottom drains (single layer floor), and all are supported by concrete.
Foundations have been excavated if necessary.
A layer of plastic sheeting is laid on the bottom.
Reinforcing is in place on top of the plastic and is supported 10 cm off the ground.
The measuring marker with the various levels of the pond is in place.
When the concrete is ready, there will be no time for the above. Please take note this is a very uncomfortable job that lies ahead. It is no easy task to stumble around at the bottom of the excavation, trying to place those oversize feet neatly between the reinforcing while a constant stream of concrete is poured into the excavation. I have seen the reinforcing end up on the bottom with all this activity going on, making the use of reinforcing valueless.
Concrete can be mixed by hand or concrete mixer or ready mix can be ordered. If you are one of the guys with the nice goldfish pond that did not read the section about planning, the concrete can be mixed by hand. For big ponds, it may be the best option to order ready mix. The decision at the end of the day if yours, but here are some points to consider:
If concrete for a big area is mixed by hand or small concrete mixer, the consistency of the mix may differ and weak areas may result.
If the pond is located far from the road, it is unavoidable to mix concrete yourself unless you have a small army of helpers with wheelbarrows.
The truck delivering the concrete must not be allowed onto your driveway. The driveway will be destroyed.
If you plan to bring the concrete by wheelbarrow from the mixing site or the delivery truck, scatter a layer of sand over existing paving to prevent spilled concrete to set on it.
It is very easy to underestimate the amount of concrete needed, especially on a shaped pond bottom.
The final layer of the floor will be rendered, so do not waste too much time to get a perfect finish. Just get it level or shaped correctly.
Leave at least a centimetre between the top of the concrete and the rim of the bottom drain to allow for finishing.
Vibrate the concrete well to get rid of all the trapped air, especially around the bottom drain and pipes.
Last Updated on Friday, 20 February 2009 20:13