Ply lining a floor without drilling?

[marky911]

Trouble is some of the dips are an inch deep and screed is apparently only good for 6mm.

Also as mentioned in my refurb thread the asphalt was laid after the cement skirtings so I need to damp proof the 20mm band around the edge of the floor. I also have areas the width of a wall where walls have been removed. So about 150mm x 20mm deep. These need to be damp proof too.