Drainage is the natural or artificial removal of surface and sub-surface water from an area. It is important that water does not lie against the base of the dwelling walls. Surrounding paths and ground levels should be at a gentle angle to carry water away from the walls. Ensure downpipes do not expel stormwater onto lower walls or ground levels. Ideally this water should be carried away by a drainage pipe to the stormwater outlet. Ground levels may also need to be lowered to expose a buried damp proof course system.

Sometimes this becomes a difficult task especially in old city areas where there has been a progressive build-up of road pavements. Some buildings in these areas are left in low-lying ground levels surrounded by what is effectively known as a 'levee bank'. A levee bank raises the ground level due to deposits of sediment over time and potentially changes the pathway of water flow.


Installing a drainage system

  • soil is escavated to a safe depth exposing the lower wall level.
  • walls are cleaned from soil and debris
  • a full coat of UV stable rubberised membrane is applied with full reinforcement
  • 2 further coats of UV stable rubberised membrane are applied
  • membrane protection board is installed along wall
  • a layer of blue metal is filled in the trench. This acts as a pathway or channel, directing any water along the trench
  • an agricultural pipe fitted with a sock is installed along the trench and connected to the nearest stormwater
  • pipe is covered with another layer of blue metal
  • trench is backfilled with soil.

In cases of constant heavy water flow, a pit is installed and fitted with a water pump . The water is removed mechanically with a water pump directing the water through the pipe to the stormwater outlet.