Waterproofing Under Tiles in Warsaw — Leak Protection

Tiles on their own are not waterproofing. Water gets in through grout joints, cracks in the grout, and wall junctions. If there is no proper waterproofing under tiles in a bathroom or shower, sooner or later it will leak. In Warsaw apartment blocks this matters even more, because flooding the neighbour below means not only repair work but compensation as well. Mapei Mapelastic, Weber.tec 822, Ceresit CR 166, Sika — tested systems we use every day around Warsaw, from Praga Poludnie to Bemowo.

How much does it cost and what affects the price

The price depends on the size of the area, the type of room (shower, full bathroom, kitchen), the number of coats, and the product selected. For bathrooms, liquid membrane is the usual solution. Joints and corners are strengthened with tape — priced as a separate item. Materials are billed separately. Current prices are shown in the table below.

Service	min	max
Waterproofing under tiles	30 zł/m²	60 zł/m²
Substrate preparation for tiles	40 zł/m²	80 zł/m²
Old tile removal	40 zł/m²	100 zł/m²
Standard tile up to 60 cm	120 zł/m²	160 zł/m²
Epoxy grouting	40 zł/m²	70 zł/m²

How the work is done on site

1. Substrate inspection. We inspect the screed for cracks and uneven spots. Waterproofing goes only onto a properly prepared surface — level, clean, and dry.
2. Priming. One or two coats of deep-penetrating primer to improve bonding.
3. Joint reinforcement. Elastic tape (Mapei Mapeband, Ceresit CL 152) is installed at wall-floor and wall-wall junctions and around pipe penetrations.
4. First membrane coat. Liquid membrane (Mapei Aquadefense, Weber.tec 822, Ceresit CR 166) applied with a roller or brush. Walls — at least 20 cm high; in the shower zone — up to the ceiling or at least 20 cm above the shower head.
5. Intermediate drying. 4-12 hours between coats depending on the product and temperature.
6. Second coat. Put on perpendicular to the first to get even coverage. Two coats are the standard.
7. Inspection. After full curing (24-48 hours) we check for any gaps or damage. Only after that does tiling start.

Common waterproofing mistakes

• Single coat — not enough thickness and easy to miss spots. Two coats minimum.
• No tape at corners — corners and junctions are the first places where the membrane gives way.
• Applying on a damp substrate — the membrane does not adhere properly and starts peeling.
• Waterproofing the floor only — shower walls left without protection. Water gets in through wall grout joints.
• Damaging the membrane during tiling — walking on it, scratching it with tools.
• Skipping pipe penetrations — the weakest spots, which need separate treatment with collars.
• Cheap uncertified products — saving money at first, then ending up with a leak within a year.

What to prepare before the technician arrives

• Screed cured and dry (minimum 28 days for cement). Cracks repaired.
• Surface cleaned: no dust, rubble, or adhesive residue.
• Pipes installed — waterproofing is done after plumbing, before tiling.
• Waterproofing bought: Mapei Aquadefense, Weber.tec 822 or Ceresit CR 166.
• Elastic tape for corners.
• Deep-penetrating primer.
• Pipe collars if needed.
• Room temperature at least +10 C.
• Ventilation for drying.
• Room emptied of furniture and fixtures blocking access to the walls.

A real case from Warsaw

In a new-build on Praga Poludnie, bathroom 7 m². The client was renovating from zero: screed, pipe runs, and waterproofing all had to be done before tiling. The screed had micro-cracks — we filled them with repair compound and gave it time to dry. Primed the floors and walls. Corners and pipe passes reinforced with Mapei Mapeband. First coat of Mapei Aquadefense — roller on the floor, brush on the walls (shower zone to ceiling, other walls 30 cm up). Dried for eight hours. Second coat perpendicular. After 24 hours — inspection: membrane continuous, even, blue (Aquadefense changes colour when cured). The tiler arrived the next day. Six months later — not one leak, neighbours happy (compatible with Paradyż, Tubądzin, Cersanit and similar).

Frequently asked questions

Is waterproofing mandatory in a bathroom?

Yes. Tiles and grout are not waterproofing. Water gets through the joints. Without a membrane, a leak into the flat below is only a matter of time.

Is one coat enough?

No. One coat can leave gaps and does not give enough thickness. Two coats are the minimum.

Which product is best?

Mapei Aquadefense, Weber.tec 822, Ceresit CR 166, Sika — all are well proven. The right choice depends on the substrate.

Is waterproofing needed on walls?

In the shower zone — mandatory, at least up to shower head height. Behind the bath — minimum 30 cm from the floor.

How long does waterproofing take to dry?

Between coats — 4-12 hours. Full curing before tiling — 24-48 hours.

Can it be applied to plasterboard?

Yes, on moisture-resistant board (green type). Standard plasterboard is not suitable in wet areas.

What happens without waterproofing?

Water gets through the joints, damages the screed, and reaches the flat below. Repair costs are much higher than waterproofing.

Is corner tape necessary?

Yes. Corners are the weakest point. Without reinforcement, the membrane tears first at the junctions.

Are materials included in the price?

No. Waterproofing, tape, and primer are bought by the client.

How long does bathroom waterproofing take?

1-2 days: priming, reinforcement, two coats with drying in between. Plus a day for full cure before tiling.

Who does the work

Waterproofing under tiles is done by technicians who know membrane systems and manufacturer requirements. This is not just painting a wall — the order of layers, drying times, and proper reinforcement all count. We work with Mapei, Weber, Ceresit and Sika. We cover all of Warsaw. Call or message to discuss your project.