Yes, waterproofing is a crucial step in any tub to shower conversion. Showers are prone to moisture exposure, and improper waterproofing can lead to water leaks, mold growth, and structural damage. A professional contractor will ensure that proper waterproofing measures are taken during the conversion process. They will use high-quality waterproofing materials and techniques to create a watertight enclosure, protecting your bathroom and ensuring the longevity of the new shower.