Yes, showers, wet rooms and the areas around baths should be tanked (waterproofed) before tiling. Although porcelain tiles absorb almost no water, water can soak through grout joints and some ceramic tiles, potentially damaging the wall or floor behind. There are two main ways to tank an area:
- A tanking kit: a liquid waterproof membrane painted onto the wall or floor, with tape for joints and corners.
- Water-resistant foam backer boards: lightweight boards fixed in place of plasterboard. You'll need to seal the joints and screw holes with the tape and sealant recommended by the manufacturer.
Whichever you use, follow the manufacturer's instructions.