Continuous digging for a week or two we really got stuck in. Two diggers on the go and the dumper truck we soon got into a rhythm. Taking around 2 weeks in total, countless grab lorry loads later we had excavated the three largest ponds and made a start on the two long trenches consisting of 6 ponds per trench (these to be finished at a later date).
Preparing the three largest ponds for the concrete floor we set out the perimeter of the ponds with string lines then marked out the drain positions. Dry fitting all of the pipe work first to check their position. We then laid the bottom drains, pipe and swept bends onto a concrete bed. Carefully making sure everything was level and positioned correctly.
Once we had set the drains and 4″ pipe work we glued up the 1″ air pipe and set that into position.
Our next job was to prepare the rebar sheets to reinforce the concrete base. Setting these on top of bricks made sure the rebar sat nicely within the concrete base.
The last day before we broke up for the Christmas break we had a huge day ahead of us. Ponds dug, drains in, pipework in, rebar in. It was time for concrete, all 18 m3 of it in one day!
Concrete was pumped into the ponds one by one. After a messy hour or two we had poured all 3 bases. It was then time to finish them off by levelling them with a piece of 4×2 wood cut to the width of the ponds and then smoothing them off with a float, a lot easier said than done given the width and length of the ponds. By the time we got to the last pond, we could tell the concrete was starting to set which made life much more difficult! Dragging our legs through the concrete it proved to be a good workout. After a gruelling few hours we completed the bases.
In the new year it was time to start the block work on the three largest ponds. Our first major delivery arrived from the builders merchants, Over 1200 hollow blocks, tonnes of sand ballast and cement all ready to go. While the concrete floor was poured, we positioned strips of rebar along the perimeter to sit inline with the blocks, this was done so that the floor and the walls are effectively tied together. On these large ponds there is tremendous water pressure, the majority of course being in the lower 1/3 nearest the bottom. Once the first three courses had been laid we filled the blocks with 12mm rebar rods and concrete. We repeated this again on the top 5 courses. 8 courses in total, 12 mm rebar throughout, and around 5-6 tonnes of concrete poured in the cavity. Both mixers were working overtime for days on end. Three ponds blocked and looking good!
Finishing off the blockwork we situated the skimmers in place and ran the pipework for the skimmers around the outside of the pond wall. Then creating a collar of concrete around the pond, this would be the base for the facing brickwork to sit on.
To be continued….