Bathroom Renovation

Waterproofing done right, before a single tile goes on the wall

A bathroom renovation lives or dies on what happens before the tiling — correct waterproofing (tanking) in wet areas, since a beautifully tiled bathroom with poor waterproofing underneath will eventually leak into the floor or the room below, however good it looks on the surface.

Tanking is the waterproof membrane system applied to floors and, particularly, shower and bath surrounds before tiling begins, and it's the part of a bathroom renovation that matters most but is entirely invisible once the job is finished, which is exactly why it's worth understanding rather than skipping past. Applied correctly — to the floor, up walls in wet areas to an adequate height, and with particular attention to corners, pipe penetrations and the shower tray or bath junction, since these joints are where tanking most commonly fails if rushed — a properly tanked bathroom prevents water getting past the tiled surface into the floor structure or through to a ceiling below, which is a genuinely serious and expensive problem to fix retrospectively once tiling is already down. Plumbing renovation is usually part of a bathroom project too, whether that's repositioning a suite, upgrading pipework that's reaching the end of its life, or improving water pressure and flow to a new shower — and, like a kitchen, first-fix plumbing and electrics need completing and testing before tanking and tiling cover them up. Tiling itself, once the waterproofing is sound, is where most of the visual decisions happen — tile size, layout, grout colour — but it's worth being clear that tiling is the finish, not the waterproofing itself, and a bathroom is only as good as the tanking underneath it.