Anyone know what I do with this membrane before laying the floor?

[Roz]

This was installed by the window fitters, my instinct is to cut it back and potentially silicone along it on the inside. Anyone have experience? 
 

I’m about to lay engineered oak floor onto this slab after cleaning it

 

 

[markc]

Turn it upwards, lay floor and then trim back to floor level. This way leaves the membrane with an up stand on the inside to prevent any water travelling back and under the flooring

[Roz]

1 minute ago, markc said:

Turn it upwards, lay floor and then trim back to floor level. This way leaves the membrane with an up stand on the inside to prevent any water travelling back and under the flooring

Thanks Mark! I was worried about the idea of water coming in and just sitting there against the wood of the door? 
 

Otherwise this sounds like a simple plan!