Repairing DPM after excavation for waste pipe

[SparrowHawk99]

I'm having to excavate some 500mm below FFL to fit a new inspection chamber and the DPM is some 200mm below so I cannot avoid puncturing it. It looks to be in relatively good condition where I have exposed.

My question is how do I water proof the area to stop rising damp? Thanks

 

[Blagard]

Essentially you need to get a new piece of DPM to overlap with the old as far as possible so cut the old DPM in the middle of your excavated area and fold back for access. Use some duct tape to hold the new piece in place when you reinstate.

 

[SparrowHawk99]

Can't see how this would work mate?