This is a standard waterproofing treatment approach for bathroom during new construction and renovation. The waterproofing treatment work process includes: 1. Back filling and PCC Work 2. Surface cleaning and preparation for coating 3. 1st layer chemical coating 4. Concrete chamber construction at corner areas with cement mortar in mix with waterproofing chemical 5. Installation of waterproofing membrane sheet 6. 2nd layer chemical coating 7. Surface drying and finishing