Filling a void between doorframe and wall

[Bobharford]

I have a vertical space between door frame and the plasterboard wall, top to bottom about 3cm width I need to fill it so I can finish the wall decoration. There is nothing to plaster too so I tried expanding foam but is is to spongy to put filler to, would bonding plaster be good at adhering to the foam to give a firm base to put finish on?
Thanks

 

[noseall]

I have a vertical space between door frame and the plasterboard wall, top to bottom about 3cm width I need to fill it so I can finish the wall decoration. There is nothing to plaster too so I tried expanding foam but is is to spongy to put filler to, would bonding plaster be good at adhering to the foam to give a firm base to put finish on?
Thanks

If we cut a new door opening into a wall, we make the opening roughly 50mm wider than it needs to be. This so that we can dab a 12.5mm thick, piece of plasterboard up each jagged cut brick jamb and get it perfectly plumb for the door casing. You could say fix a length of 100mm x 50mm timber up one of the jambs and use dabbed plasterboard of the other?

 

[Bobharford]

Thanks the void is t a right angle as the door opening is recessed however using your suggestion I think I can make it work
Thanks