Illustration for how to fill drainage pipes.

Filling around drainage pipes

Depending on the type of pipe you intend installing, there are different guidelines that should be followed.

When laying new pipe or rerouting existing pipe lines, you should bear in mind the type of materials used to prevent destroying the pipe. Next to the pipes you should avoid materials with large stones as over time these can press holes or crush pipes.

You should also remember that pipes carrying water must be laid with a specific incline and at a certain depth to prevent the water from freezing.

You will need:

  • Water level
  • Wheelbarrow
  • Spade
  • Folding rule
  • Compactor/tamper

We recommend these materials:

  • Macadam e.g. 11/16
  • Drainage pipe
  • Geotextile fabric

Do this

  1. Check whether there are any other pipes in the ground that need to be taken into consideration before starting to excavate.
  2. Clear any vegetation from the soil. The width of the trench should be at least 50 cm, as the bed of macadam must be compacted to avoid settlement in the structure.
  3. Excavate down to the recommended depth (frost-free). The depth varies depending on the climate zone you live in. Ask about the recommended depth for the drainage pipe at the point of purchase, they should know.
  4. Start by laying the geotextile in the trench as a material separating layer. Fill with macadam 11/16 about 15 cm. Remember to lay it at the right incline, the recommended drop is 1:200. Compact the bed using the tamper.
  5. Position the pipe. Check that the incline is correct, recommended drop 1:200.Fill with macadam 11/16 about 30 cm from the crown of the pipe.
  6. The backfill must cover the whole width of the pipe trench.
  7. Fold the geotextile fabric and place this overlapped approximately 40 cm.
  8. Now fill using the masses that were previously excavated. Compact the surface.