Bathroom Waterproofing & Tanking in London.

Why tanking decides longevity

Waterproofing is the only stage of your bathroom you'll never see — and the only one that can ruin everything.

Most bathroom problems we get called to in London look like a tile issue, a grout issue or a silicone issue. They almost never are. The actual cause is usually a failed waterproofing layer behind the tile — a wet zone where the original installer skipped the corners, didn't tape the drain flange, didn't prime, or treated tanking as "optional" because the budget was tight.

Build Masters Group Ltd treats waterproofing and tanking as the foundation of every wet zone. It's either done properly with a system the manufacturer specified — or it's not done at all. There is no middle ground.

What "tanking properly" actually means

• Substrate prep — the wet zone surface is dry, level, free of dust and properly bonded before anything else.
• Primer — manufacturer-specified primer matched to the membrane and substrate, applied to coverage rate.
• Membrane — liquid or sheet membrane applied to the whole wet envelope (floor and lower walls) to the right thickness.
• Taped corners — internal corners, junctions and pipe penetrations sealed with reinforcement tape embedded in membrane.
• Bond-breaker at the drain — proper treatment of the drain flange so movement doesn't tear the membrane.
• Perimeter seal — splash-zone treatment up to a sensible height around the bath, basin and shower zone.
• Photo record — the finished tanking is photographed before tiling, so the client has documentation of what's behind the wall.

When you need standalone waterproofing (not as part of a renovation)

We are often called by London homeowners with a bathroom that's only a few years old where the shower is already leaking. Usually it's the membrane — sometimes there isn't one. The fix is to strip the affected zone, treat the substrate properly, install a new membrane, then re-tile and re-fit. It is more work than "patching", but patching over failed waterproofing rarely lasts and almost always returns.

Tanking as part of wetroom installation

If you are planning a new wetroom in London, tanking is automatically part of that scope — there is no separate decision. The same logic applies to a full bathroom renovation with a walk-in shower.