How do you polyurethane terra cotta tile floor?

To polyurethane a terra cotta tile floor, first clean the surface thoroughly to remove any dirt, dust, and grease. Allow the tiles to dry completely before applying a primer specifically designed for porous surfaces, if necessary. Once the primer is dry, apply a high-quality polyurethane sealer using a brush or roller, following the manufacturer's instructions. Allow adequate drying time between coats, and typically apply at least two to three coats for optimal protection and finish.