Do i need DPM on wooden subfloor before laying laminate? Help, advice, information, answers and tips on all types of flooring from laminate and carpet to timber and vinyl

[Arpit.pasari]

Hi , I recently brought 1930 bungalow. I am thinking to fit laminate floor ( 8mm engineered wood flooring) on my own.
Bungalow have wooden subfloor (suspension). I am thinking to to use wood fibre for underlay. Do i need to put "Vapour Barrier Polythene as a Damp Proof Membrane" before underlay. Or it's just optional?
Is there any disadvantage if i go with DPM as well (DPM + wood fibre underlay + laminate floor).

Thanks , Arpit