You're saying downstairs as in basement or main floor? If basement you'll need some kind of waterproof underlay like Delta FL or whatever.
The walls and floors covered in OSB might be a little overwhelming if it's all varnished - a little too much yellow wood.
The neighbours did their kitchen floor in OSB, turned out well - durability will depend on type and number of coats of preservative.
You're saying downstairs as in basement or main floor? If basement you'll need some kind of waterproof underlay like Delta FL or whatever.
The walls and floors covered in OSB might be a little overwhelming if it's all varnished - a little too much yellow wood.
The neighbours did their kitchen floor in OSB, turned out well - durability will depend on type and number of coats of preservative.