Yes, it is possible to apply a new layer of industrial sealer over an existing one. However, it is crucial to ensure that the existing sealer is clean, intact, and compatible with the new sealer. This ensures that the new sealer adheres properly and provides the desired level of protection. Applying a new sealer over an old one can help reinforce the seal and extend the life of the project, particularly in environments where the seal is subjected to heavy wear and tear.