Advice needed on covering underground drainage pipe

9 Sep 2015
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United Kingdom
we have just laid a run of liner drainage in our brewery which then connects to an underground 110mm pipe (in the photo) and have connected it into the drainage system.
We now need to concrete over the top of this pipe.
are we ok to surround the pipe in pea shingle then pour concrete on top the are will only ever be walked on so no vehicles or is there something else we should do



  • brewery drainage.jpg
    brewery drainage.jpg
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Wack the pea gravel down well and cover it with some placky bags to stop your cement trying to soak through it.
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Before covering up any below ground drainage its good practice to test first. As Noseal says, pipe bedding to the underside of the existing concrete slab, ensure the new pipe is also laid on pipe bedding, and then top up with concrete. You may also want to consider tying the new concrete slab to the existing, you may otherwise have differential movement between the new and existing slabs. Is it being used for foul or storm water? and what system have you connected it to (foul or storm). Could you just confirm there is no existing Damp Proof Membrane below the existing slab.
Last edited:
thanks cAtLeYx
its being used as a brewery so mainly it will be only water going down. as per the photo ive just layed the sump box for the linnier drainage so far and the after that ive created a foul air trap. later this week i plan on laying the rest of the drainage channel. we have rented an empty unit for 3 years so if all goes well we will need bigger premises, so will end up digging up the drainage and putting it back the way it was. there was no Damp Proof Membrane below the existing slab
Thanks jonaathan. You quote "mainly water" will there be any other substances that may require filtering prior to exiting into the existing system? Chemicals etc? I assume the trap is between the ground connection and the sump as you state its already installed? If there was no DPM installed previously there would be little point in adding this the the make up of the reinstatement works.

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