WEEKEND TRAINING: Why Bathrooms Leak Even After Full Tiling (And what most builders get wrong) Bathrooms are one of the most commonly repaired areas in a building — not because of bad tiles or fittings, but because moisture management was never properly addressed during construction. Here’s a breakdown of why bathrooms leak and what you should know ,whether you're a builder, consultant, or property owner: 💧 1. Tiling ≠ Waterproofing Most people assume that once tiles are installed, water can no longer pass through. But the truth is: Ceramic and porcelain tiles are water-resistant — not waterproof. Grout lines are porous, especially when cracked or unsealed. Over time, water seeps through and collects in the screed layer beneath. 🧱 2. No Moisture Barrier Beneath Screed A key mistake during construction is skipping the waterproofing membrane before pouring screed. Here’s what often happens: Screed absorbs water from daily use (showers, splashes) Capillary action pushes moisture sideways and downward Moisture reaches concrete or ceiling slab, leading to paint bubbles, stains, and mould on the lower floor ⚠️ 3. Failure at Drain Edges and Pipe Penetrations Areas around floor drains, pipe outlets, and toilet bases are the most vulnerable. If not sealed properly: Water bypasses the tile layer completely Leaks show up at floor junctions or corners In severe cases, entire tile sections become loose 🔁 4. Thermal Expansion and Cracks As tiles heat and cool daily, micro-movement happens. If the waterproofing layer below isn’t flexible, it cracks — and water finds its way through. 🛠️ What’s the Proper Bathroom Moisture Control Approach? 1. Waterproof the substrate first — especially floor slab and lower wall zones 2. Use a flexible membrane (liquid or sheet) beneath screed 3. Apply sealants around pipe outlets, wall joints, and drain corners 4. Slope floors toward drains properly — to avoid stagnant water 5. Once tiling is done, seal grout and regularly check high-risk areas 💬 Discussion Time: Have you seen leaks from a “new” bathroom before? What methods do you use on your sites for wet area protection? Any mistakes you’ve seen other builders make? Reply below — let’s talk. We'll post answers and live case reviews tomorrow in the PROSEAL WhatsApp Channel. #constructiontalks #waterproofingeducation #sitewisdom