How to use DPM when extending a shed concrete slab?

[g8dy]

Ive read the typical process of laying a concrete slab is Compacted hardcore > sharp sand > DPM > Concrete. How would you incorporate a DPM when extending a concrete slab though? Would you leave the face of the concrete slab that will be in contact with the new slab bare with no DPM (like this sketch below). Or would you face all sides with the DPM and cut holes in the DPM for the dowels to poke through?

Option 1

Option 2 - DPM goes all around and dowels poke through

 

[clogs]

u need to use thin closed cell matting.....
similar to the stuff under flooring laminate.......
on bigger jobs, say a factory floor they use 6mm to 12mm for the same job.....

when the floor is cured knife of any waste and use a tube sealer to stop the dirt getting in.....I like polyurethane over Silicone...

 

[g8dy]

u need to use thin closed cell matting.....
similar to the stuff under flooring laminate.......
on bigger jobs, say a factory floor they use 6mm to 12mm for the same job.....

when the floor is cured knife of any waste and use a tube sealer to stop the dirt getting in.....I like polyurethane over Silicone...

Hi, im slightly confused, where does the closed cell matting get used in this?