damp proof repair

[Hack]

hi, I'm after some advice as to how (or whether it's worth it) to repair a small section of plastic damp proof membrane - at least I'm guessing that's what it is.
I have removed a bath with a view to turn the room into a utility room and whoever installed the bath pulled up the concrete floor to lay the waste pipe. This has damaged a small section (about 15cm x 30 cm) of the plastic sheeting between the concrete and the hardcore underneath. I still want to use the waste pipe as washing machine waste and am laying new concrete in the surrounding area. This will level the floor and allow a washing machine and cupboard to be installed. I was planning on leaving the waste pipe 'exposed' but boxed in (ie not cemented over).
Is it worth repairing and if so what's the best way? i'm a bit loath to buy a huge sheet of plastic for such a small hole...will a liquid sealer be ok or any think plastic sheet?
Thanks for any tips

 

[Hack]

anyone? Bueller? where are all those damp proof experts whose posts I've been reading!

 

[noseall]

not worth worrying about.

 

[JerryM]

noseall is probably right (he usually is).

i'm always terrified of getting even the slightest damp smell even accepting the damp itself is of no concern (being too small).

consequently i would always repair it – given the effort is small. i would just use a thk piece of plastic as u suggest. i generally lap it up the sides of the existing concrete and butter it with mortar on the underside.