DPC strip behind wall battens

[OldieNewbie]

If your batting out a wall with 2’ x 2’ should you also have a strip of DPC behind them? Or if the wall is sealed first with a coat of sand and cement would that do rather than the DPC?

 

Or is it totally decided by designers? 

[nod]

Dpc 

[OldieNewbie]

Thanks Nod. Is there ever a reason why DPC would not be used?

 

I pass by two different house renovation jobs on my way to work and they’re surprisingly at similar stages. One project has DPC behind timber battens the other doesn’t.