Dpm repair

[600rob]

Im in the process of installing a ground anchor in a concrete garage floor.
so far ive made the hole in the existing concrete floor and removed the required amount of material to get the required hole depth.
I now need to re line the hole with a patch of dpm where i had to cut out some of the existing one. As you'll see in the photo ive drilled through the dpm in quite a few places.
View media item 98504
Whats the best way for me to sort this out?
Can i just tuck the patch repair up the sides of the hole and under the existing dpm or should i use some sort of joining tape?

Thanks

 

[600rob]

how does this approach sound?

remove some material from the underside of the existing (Damaged) dpm then wedge in the new DPM with an overlap of around 100mm.

will probably tape up the joint for good measure with some of this stuff

http://www.screwfix.com/p/polythene-joint-tape-black-50mm-x-33m/44221

 

[John D v2.0]

Is it damp underneath at the moment? If not it's less of a worry, especially being not an inside room.
In the absence of any more informed answers I'd say it's hard to get a watertight seal with patching in. Perhaps try some liquid of some kind, maybe some sand and cement with a waterproofing additive.

 

[600rob]

it doesn't seem to be damp...

the sand and stones below the membrane can be quite easily removed by hand and the sand is largley dry and crumbly in the hand

if anything there may be what seems like a very small amount of moisture in the sand but not enough to dampen a bit of tissue if i squeeze a handfull of the sand with a bit of tissue surronding it