Depends on expectations / how perfect you need it but Sheet Lino is pretty unforgiving of less than perfect subfloor. I wouldn’t use anything less than 18mm over very well levelled (ideally freshly sanded boards). Any joins between ply sheets need careful attention to stop them showing - so lots of fixings and filling and sanding. Check the marmoleumn data sheets for installation. They might even say use a latex self level screed over the ply. …..So I’d be concerned about shims and 2mm ply personally !!
Depends on expectations / how perfect you need it but Sheet Lino is pretty unforgiving of less than perfect subfloor. I wouldn’t use anything less than 18mm over very well levelled (ideally freshly sanded boards). Any joins between ply sheets need careful attention to stop them showing - so lots of fixings and filling and sanding. Check the marmoleumn data sheets for installation. They might even say use a latex self level screed over the ply. …..So I’d be concerned about shims and 2mm ply personally !!