5.3 Drainage below ground

Also see:

4.35.1

5.3.14 Protection of pipework

Drainage systems shall have pipework adequately protected against damage. Issues to be taken into account include:

  1. pipes passing through substructure walls
  2. pipework under finishes
  3. movement joints.

Pipes passing through substructure walls#

Where drains pass through structural elements; allowance should be made to accommodate movement.

Pipes passing through substructure walls should accommodate movement by:

  • a 50mm clearance all round
  • a sleeve, with 50mm clearance all round and suitably sealed, or
  • bedded pipes, connected on both sides of the wall with flexible joints located as close as is feasible to the outside face of the wall but at a maximum of 150mm from the face of the wall.

Flexible joints should be made in accordance with the pipe manufacturer’s recommendations.

Pipework under finishes#

Where drains pass under roads and drives, the final compaction should be sufficient to prevent later settlement.

Movement joints#

Where rigid pipes are to be encased in concrete, movement joints should be:

  • provided around the spigot next to the socket either at 5m maximum intervals or at each joint
  • 13mm thick compressible board.

Last updated: 2nd January 2024

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