Canada uses both as the building trade is still dominated by US products so we still use 2 x 4s (although they are not actually 2" or 4" - don't get me started). We still say PSI for pressure and no one here understand kilopascals.
We also say a pint of beer, which can be 12ozs (traditional Canadian breer bottles), 16ozs US, or 20 UK (what we expect).