Section 5.1.4
Drainage Under Floors
Drainage below ground is essential for removing foul water from the property. Care needs to be taken with gradients to avoid blockages, movement and position in relation to above ground services.
Acceptable methods include;
Drainage running through ducting and providing 50mm clearance around the pipe work.
Or, building the pipe work in solid to the substructure and providing flexible joints within 150mm from the substructure wall and within 600mm of the primary flexible joint.
Drainage passing through the substructure wall is required to provide allowance for movement.
This example shows the use of primary flexible joints, placed within 150mm of the substructure on both sides.
The secondary flexible joint placed within 600mm of the primary flexible joint.
Where suitable, pipework should come through the substructure together to reduce the number of openings.
Any bends under the ground floor must be within 2m of the access chamber.
Pipework laid onto a bed of 4mm – 10mm bedding gravel.
Gradient of pipework to be no less than 1:40 which equates to 25mm in 1m.
Long radius rest bend used at the return junction to the ground floor.
Secure bedding provided by mortar which has been neatly pointed.
Rest bend to be positioned allowing for the finishes to the superstructure (Plaster boarding, skirting etc.).
Long radius rest bend used at the return junction to the ground floor.
Secure bedding provided by mortar which has been neatly pointed.
Rest bend to be positioned allowing for the finishes to the superstructure (Plaster boarding, skirting etc.).
Provide adequate space for drainage to pass through internal walls.
