Expanded Polystyrene Sheets Directly Under Laminate?

[wau5]

Got a bedroom over an unheated garage, the only thing between them is a concrete floor/osb sheet/ some 2mm foam underlay and a laminate.
a Massive heatloss...

Was wondering how could I insulate the floor as quickly as possible with the least effort in the cheapest way...
Came up with the idea to just take up my current laminate, and pop under 50mm sheet of EPS100 Expanded Polystyrene & put the old laminate back.

Tried to search if someone has done such thing and couldn't find anything much.
Is this idea Doable/anything I'm not aware of or haven't thought about why this idea could be a failure/structurally unstable/dangerous etc?

The sheets of Polystyrene I can get here are 50x100cm in size, if the OSB wasn't so darn expensive here now I would probably put another sheet of OSB over the Polystryene, wondering If I can make do without it...

I'm aware that the correct way would be to insulate the ceiling of the garage,however It would take me 5x longer to do in my situation.

 

[Mr Chibs]

What you want to look up is 'floating floor'.

Would think you may be better with PIR insulation as it's more robust than polystyrene, and thermally more efficient... although more expensive.
Think I'd be tempted to do garage ceiling, but by the sound of it, it will be a saga.

 

[oldbutnotdead]

Floating floor as above- trouble is it'll look a bit poo unless you lift the skirting boards, you'll have a 2 inch step up into the bedroom, probably have to trim the bottom of the door.
You'd be better off (and it'll almost certainly be cheaper) putting 300mm of rockwool in the garage ceiling. Ideally you'd stick a 3x2 timber framework in to support the stuff (you could board over it later), if it's a single garage you could probably get away with slating battens and polythene as a ceiling.

 

[JP_]

Could you insulate the garage ceiling? Doesn't have to look pretty.

 

[wau5]

bumps

 

[phatboy]

bumps

You have received 2 good answers, what more do you want?

I would insulate below, between garage ceiling timbers. If they are 200mm or more, Rockwool would be fine and easy to do. Then just re-board the garage ceiling.