Waterproofing & Tankingfor Wet AreasAcross Kent
Tiles and grout are not waterproof on their own, proper tanking behind them is what actually keeps water out of your walls and floors, installed correctly before a single tile goes on.
4.9 on Google · 7 years' experience · 1-year workmanship guarantee
£10m
Public liability insurance
1 year
Workmanship guarantee
7 years
Experience tanking wet areas
4.9
Average Google rating
Waterproofing and tanking for wet areas in Kent
Waterproofing, or tanking, is the layer of boards, tapes and membranes installed onto walls and floors before tiling in areas that take direct contact with water: shower enclosures, wetrooms and around baths. It is the part nobody sees once the job is finished, which is why it is the part most often skipped.
It applies to any shower, wetroom or bath area being tiled, whether a full refurbishment, a new en-suite or a standalone shower replacement. Room size makes no difference: the failure mode is the same, water finding a way past the tile surface into the substrate.
It has to be done before tiling, never after, and it works only as a complete, continuous layer with the right tapes and corner pieces at junctions and pipe penetrations. Miss one detail and the whole system is defeated.
What you get
- Tanking systems installed as designed
- Corners, junctions and penetrations sealed
- Backer boards where the substrate needs them
- Completed before any tiling begins
- 1-year workmanship guarantee
What it costs to leave it
What happens when tanking is missed or done badly
Grout and tile joints are permeable over time, so a wet area relies on the layer behind the tiles to keep water out of the building. Where that layer is missing or badly detailed, water gets past gradually, so damage is well established before anyone notices.
The consequences build slowly: damp plasterboard, blown plaster, mould behind tiling and, in timber-floored properties, rotten joists beneath a shower or bath. Once water reaches structural timber, the repair is a building job rather than a bathroom one.
Because the tiling looks perfectly fine on the surface, poor tanking is one of the most expensive corners to cut and the hardest to detect. Treating tanking as a proper, checked stage is the only real protection.
Mistakes that cause it
- Tiling straight onto plasterboard or plywood with no waterproofing layer at all
- Missing tanking tape at internal corners, where the majority of leaks actually start
- Leaving pipe penetrations and waste outlets unsealed
- Using standard silicone as a substitute for a proper tanking system
- Skipping the upstand height needed around baths and shower trays
- Fitting backer boards without taping the joints between them
How the work runs
A process you can follow
Step 1
Assess the substrate and wet area extent
The walls, floor and existing substrate are checked, and the extent of the wet area is agreed, full wetroom tanking is a different scope to tanking around a bath or a standard shower enclosure.
Step 2
Fit backer boards where needed
Where the existing substrate is not suitable for tiling directly, tile backer boards are fitted first, giving a stable, waterproof-ready surface for the tanking membrane to bond to.
Step 3
Apply the tanking system to walls and floor
A liquid or sheet membrane is applied across the whole wet area, built up to the correct thickness and left to cure fully before moving on, so the finished layer is continuous rather than patchy.
Step 4
Detail corners, junctions and penetrations
Purpose-made tanking tape and corner pieces are used at every internal corner, wall-to-floor junction and pipe penetration, since these are the points a generic membrane alone cannot properly seal.
Step 5
Check and sign off before tiling begins
The completed tanking is checked for full coverage and correct upstand heights before any tiling starts, since this is the last point at which any gap can be corrected without disturbing finished work.
What you actually get out of it
Water stays where it should
A continuous tanking system stops water reaching the structure behind the tiling, regardless of how the grout ages over time.
Protects the substrate from day one
Backer boards and correctly sealed membranes stop timber, plasterboard and screed from absorbing moisture that would otherwise cause rot or mould.
Avoids the most expensive repairs in a bathroom
Correcting a leak after it has reached a floor joist or an adjoining ceiling costs far more than doing the waterproofing properly the first time.
Built to last as long as the tiling above it
Because it is installed as a complete system rather than patched, tanking does not degrade at the same rate as exposed silicone joints.
Covered by a 1-year workmanship guarantee
The tanking, like the tiling above it, is guaranteed for a year from completion.
Coordinated with the rest of the bathroom
On a full refurbishment, tanking is planned alongside any plumbing or electrical changes so nothing is fitted before the waterproofing is complete.
Waterproofing & Tanking in detail
Membrane systems and backer boards
Liquid tanking systems are applied by brush or roller in multiple coats, building up a flexible, seamless membrane that follows the exact shape of the wall and floor, including any awkward junctions or pipe boxing. Sheet membranes achieve a similar result using a bonded fabric or polythene sheet, which some installers prefer for large, flat areas where consistent thickness matters most.
Rigid tile backer boards, typically a cement or foam-core board, are used where the existing wall or floor substrate is not suitable to tile onto directly, or where extra rigidity is needed, such as around a tiled shower niche or bench. The joints between boards are taped and sealed as part of the tanking process, since an untaped joint is simply a gap in the waterproofing layer.
Waterproofing & Tanking: your questions answered
It depends on the size of the wet area and the substrate condition, so it is priced per job after a site visit rather than as a flat rate, and it is usually included within a fixed tiling or bathroom refurbishment price rather than billed as a separate extra.
Liquid membranes need time to cure fully between coats, so this stage typically adds a day or two to the schedule depending on the size of the area and the number of coats needed, and tiling does not start until the tanking has fully cured.
Yes. Grout and sealed joints reduce water penetration but do not stop it completely over time, especially at corners and junctions, which is exactly where tanking is designed to protect the substrate behind the tiles.
Not without removing the existing tiling first, since tanking has to sit directly on the substrate beneath the tiles. If a leak is suspected in an already-tiled wet area; it is worth having it assessed before deciding how much needs to come up.
Where the existing wall or floor is not suitable to tile onto directly, yes, backer boards are fitted first, then taped and tanked as part of the same waterproofing system.
Yes, it carries the same 1-year workmanship guarantee as the tiling above it, and all work is covered by £10m public liability insurance.
Not always. Shower enclosures and wetroom floors need full tanking, while areas around a bath usually need tanking to a sensible upstand height, and general walls away from direct water need a waterproof adhesive and properly sealed grout rather than full tanking.
Yes, tanking and waterproofing is carried out as part of tiling and bathroom refurbishment work across Sevenoaks, Tunbridge Wells, Maidstone, Bromley, Dartford and the wider area, scheduled Monday to Saturday, 7am to 9pm.
Where James works
Sevenoaks · Tunbridge Wells · Chislehurst · Orpington · Goudhurst · West Malling · Beckenham · Bromley · Maidstone · Tonbridge · Sidcup · Bexley · Swanley · Dartford · Petts Wood · West Wickham · Pembury · Edenbridge · Westerham
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