PROJECT 37
The contractor had to consider several factors as the end point was to be placed quite far from the start of the drainage point and extended around the border in a right angle . As this was a living home , catering for the customer ’ s daily living was the main factor . Digging up loads of sand , moving paving stones and catering for stone deliveries made the project a very challenging one .
Due to the depth of the subsoil drain it was not possible to get natural runoff , therefore a manhole , complete with cover and frame had to be built in the garden as a catchment area below the ground . The pump could then be installed with its electric connections and overflow to the exterior or with the option to reuse the water for irrigation purposes . PA
We let Darryl Brainin explain the process .
“ The problem was larger than just some water constantly soaking the grass . Because of the high level , water was constantly seeping through the brick paving at the back of the house and was in the shade , the area was constantly saturated causing mould to grow and the potential for people to slip . So , from the highest point we excavated a trench alongside the boundary wall in the passage around the back wall to the lowest point in the garden area where we built a collection sump . A submersible pump with an automatic float switch was installed so excess water could then be pumped into the park area where the water would follow its natural flow .
The trench was dug to be approx . 600mm and 400mm wide and Bidim cloth was laid to line the trench . We imported 19mm washed concrete stone which was used to lay on top of the Bidim cloth in a 100mm layer . On top of this we installed 100mm Geopipe which is a slotted pipe , three quarters open , and a quarter solid bottom to assist water flow . This was then covered with more concrete stone on all sides and on top with the final protruding layer of Bidim cloth wrapped over to form a ‘ square agricultural drain .’
Extra drains were installed into the weep holes from the boundary wall as well . Washed river sand was placed on top of this and remaining soil fill and finally brick paving reinstated .
October 2022 Volume 28 I Number 8 www . plumbingafrica . co . za