Plasterboard adhesive on lintel

[YorkshireMidge]

Need to stick a piece of plasterboard to the underside of a concrete lintel in a window reveal. Have some plasterboard adhesive ready to dot and dab it, but just wondered if it will stick straight on or whether it needs any surface prep such as PVA etc.

Thanks.

 

[Wayners]

I used some polymer grab along with board adhesive.
Stuck one on with silicone some years ago that's still good.
I've also used foam.
Polymer plus dot and dab adhesive would be my choice for belt and braces