What the purpose of this material ?

bob_a_builder

During some investigations into damp in a wall we came across this plastic sheet with reinforcing strands and 'plastic lumps' on the reverse side, fixed to the by the red circular fixings
This is in a boxed in section in a corner - but no internal downpipe, so not really sure why there is a boxed in corner 
Not see it before, not sure of its intended purpose ?

TELLIT01

It looks like the material they use on wet/damp surfaces to prevent water ingress.  That would tie in with the damp problem being experienced.

mandy47

Defiantly membrane used against damp. Had this in my last house.

bob_a_builder

Thanks,
Although its not actually sealed against that wall on the right hand side in any way ?

tacpot12

It's purpose is to direct any moisture to the bottom of the wall where there should be some drainage provision, and possibly even a sump. It's often used to waterproof basements. 

It's expect that it has not been continued around the wall on the right hand side because that wall was found to be dry. Any moisture at the corner should either fall down left hand side of the wall (where the plastic 'lumps' make it easy for it to do so), or it should wick through the right hand wall and evaporate. The hope is that the amount of water that makes it as far as the corner is so small that evaporation can deal with it. If the room isn't heated well, this strategy could be failing.  

WustyRex

Tanking membrane designed to direct moisture away , depending how well it was fitted and if they added an escape route for the water , it works, but looks like it didnt.