Waterproofing isn’t just a step in bathroom construction—it’s the **critical defense** against mold, structural damage, and expensive callbacks. At Neptrech Elite, we treat waterproofing as a **system**, not a single product. Here’s what truly matters.
1. Substrate Preparation: The Invisible Foundation
Even the best membrane fails on a poor surface. Before any waterproofing begins:
- Remove all dust, grease, and loose particles.
- Ensure the floor has a **minimum 1:80 fall** toward the drain (≈12mm per meter).
- Repair cracks with flexible polymer-modified mortar.
- Prime porous surfaces (like screed or concrete) to ensure membrane adhesion.
Warning:
Tiling directly over unprimed screed or green board (not cement board) is a common—and costly—mistake. Always use a stable, waterproof backing like **cement board or waterproof plywood** on walls.
2. Choosing the Right Membrane
Not all waterproofing membranes are equal. We recommend:
- Liquid-applied membranes** (e.g., polyurethane or acrylic): seamless, flexible, and ideal for complex shapes.
- Sheet membranes** (e.g., PVC or HDPE): excellent for floors but require skilled seam welding.
- Avoid cheap bitumen-based paints—they crack under movement and don’t bond well with tile adhesives.
Ensure your membrane is **compatible with your tile adhesive** (check manufacturer specs!). Incompatibility causes delamination.
3. Critical Detailing Areas
Water exploits weak points. Pay special attention to:
- Floor-to-wall junctions: Apply membrane with a coved bead (rounded internal corner) and extend 150mm up the wall.
- Drain flanges: Use integrated drain systems or seal flanges with liquid membrane and fabric reinforcement.
- Pipe penetrations: Wrap with membrane and use flexible sealant collars.
- Door thresholds: Extend waterproofing 300mm beyond the shower zone under the door.
4. Curing & Testing
Rushing this step invites failure:
- Allow membrane to cure **fully** per manufacturer instructions (usually 24–72 hours).
- Perform a **flood test**: plug the drain, fill the floor with 2–3cm of water, and monitor for 24 hours. Check ceilings below for leaks.
- Only proceed to tiling after passing the test.
5. Post-Waterproofing Best Practices
- Use **flexible tile adhesives** (Class S1 or S2) to accommodate minor movement.
- Seal perimeter joints with **silicone**, not grout—grout is rigid and cracks.
- Re-seal silicone annually in high-moisture zones (e.g., shower corners).
Avoid Costly Mistakes—Get It Right the First Time
Our certified waterproofing specialists follow SANS 10209 and international best practices to ensure your bathroom stays dry for decades.