It is not advisable to apply TotalBoat TotalProtect 2-part epoxy barrier coat and primer over coal tar epoxy as it is generally unnecessary. If the coal tar epoxy is no longer effective, using an epoxy barrier coat like TotalProtect is unlikely to resolve the issue. Moreover, older coal tar epoxy may pose bonding challenges for TotalProtect. In cases where the coal tar epoxy is no longer functional, it is recommended to remove it by way of blasting and apply a new suitable coating directed on the product's instructions.