When u play barik make different loadouts for turrets, shield, demage and try to counter the enemys build. Try to make uncounterable loadouts, for example do not make a loadout just focusing on turrets cos thats easy to counter with bulldozer card.
Barik's primary shot is joke from far away, use this to your advantage and force the Barik to either stay in place and try to wait for help or go after you. Be ready for both of these options.
If Barik is running One Man's Scrap on a high level try to use CC (To prevent Barik destroying them himself) and avoid the turrets to prevent this form of healing.
Nearly every Barik out there has a healing card in their loadout. It provides him a heavy sustain. Cauterize is an all around counter that also works against him very well in that aspect, even without a healer on enemy team!
Tinkerin' Barik has range slightly beyond the level of Viktor. Don't even bother 1v1ing him if he even has 1 turret up, as he then requires multiple people focus firing him to bring him down.