The Ultimate Bathroom Renovation Guide: Cost, Materials & Waterproofing

Transforming Your Bathroom: A Complete Renovation Guide

A bathroom renovation is one of the most rewarding home improvement projects, offering high ROI and daily comfort. However, unlike painting a bedroom, a bathroom renovation involves complex civil work, plumbing, and critical waterproofing.

Whether you live in a high-rise in South Mumbai or a villa in Navi Mumbai, this guide covers everything you need to know.

Step 1: Complete Demolition and Stripping

The first step is carefully breaking down the existing structure. This means removing old sanitaryware, chipping away wall and floor tiles down to the bare brick and concrete, and removing old rusted GI pipes. It is highly recommended to replace all old concealed plumbing during a renovation, even if it seems fine.

Step 2: Concealed Plumbing and Electricals

Once the bathroom is stripped bare, the new layout is marked. CPVC pipes (for hot and cold water) and UPVC pipes (for drainage) are laid out. If you are installing a wall-hung commode, the concealed cistern (like Geberit or Grohe) is installed at this stage.

Simultaneously, electrical conduits are routed for geysers, exhaust fans, mirror lights, and power sockets.

Step 3: The Most Critical Step – Waterproofing

This is where most local contractors fail. Before any new plaster or tiles are applied, the bathroom floor and walls (up to 3 feet, or 7 feet in shower areas) must be meticulously waterproofed. We highly recommend a two-coat chemical waterproofing process using epoxy or specialized cementitious coatings (like Dr. Fixit or Fosroc).

Flood Test: After waterproofing, the bathroom floor must be filled with water and left for 48 hours to check for any micro-leaks to the lower floor.

Step 4: Plastering and Leveling

Once the waterproofing passes the flood test, the walls are re-plastered with a cement-sand mix. Plaster work must be perfectly plumb (straight) so that the new tiles sit flush without hollow spaces behind them.

Step 5: Tiles Work and Flooring

Now the aesthetic phase begins. For bathrooms, it is mandatory to use anti-skid tiles for the flooring. For the walls, large-format ceramic or vitrified tiles are popular as they mean fewer grout lines (which are prone to getting dirty).

Our tiles work specialists use laser levels and tile spacers to ensure perfectly aligned grout lines, filled with high-quality epoxy grout that resists fungus.

Step 6: False Ceiling and Painting

To hide the plumbing pipes of the floor above you, a false ceiling is installed. We recommend using moisture-resistant POP work or PVC panels for bathroom ceilings. The ceiling and any non-tiled wall areas are then finished with anti-fungal painting.

Step 7: Final Fittings and Sanitaryware

Finally, the WC, washbasin, shower panels, taps, and accessories are fitted. Electrical fixtures are connected, and silicone sealant is applied around joints to prevent water ingress.

Estimated Cost of Bathroom Renovation (2026)

For a standard 40 sq. ft. bathroom in Mumbai:

• Basic Renovation: ₹60,000 - ₹80,000 (Standard local brand tiles & fittings)
• Premium Renovation: ₹90,000 - ₹1,30,000 (Jaquar/Kohler fittings, premium vitrified tiles, concealed cistern)
• Luxury Renovation: ₹1,50,000+ (Imported marble, Grohe/Hansgrohe shower systems, glass partitions)

Why Hire AMS Civil Construction?

We provide end-to-end bathroom renovation solutions with a 5-year guarantee on waterproofing. If you want a zero-headache renovation, contact us for a free site inspection.