Waterproofing is the layer nobody sees and everybody pays for in the end. It sits under the tile, so a failure in it is not a local fault but a strip-out of the room. Most of the damp we are called to is not a leaking pipe — it is waterproofing done partially, at insufficient height, or with the corners skipped.
What actually gets waterproofed
Bathroom waterproofing is not a coat on the floor. It is an envelope:
- The entire floor, wall to wall, including under the vanity and under the WC.
- An upstand onto the walls around the room — at least 20 cm above floor level.
- The shower enclosure — up to shower-head height, in practice 180 to 200 cm.
- Around the bath — the wall behind and beside it, to 30 cm above the rim.
- Corners and junctions — wall-to-wall and wall-to-floor, with a dedicated sealing tape bedded into the layer.
- Penetrations — floor drain, tap outlets, the WC connection. Every hole is a potential failure point.
The wall-to-floor junction is where failures concentrate, because the structure moves slightly over the years. A flexible corner tape is not a refinement — it is what lets that movement happen without tearing the membrane.
Methods, and when each applies
- Two-part flexible cementitious. The default in Israel. Applied in two cross-directional coats, suits floors and walls, tolerates slight movement.
- Liquid polyurethane membrane. Higher flexibility, good on balconies and areas with thermal movement. More expensive and more sensitive to application conditions.
- Bituminous sheets. Common on roofs and balconies, less so in internal bathrooms because of the difficulty at corners and penetrations. See roof sealing and balcony sealing.
- Pre-formed boards. Coated polystyrene boards for building a shower enclosure. Fast and accurate, more expensive in material and cheaper in time.
The correct sequence
- Strip to substrate, clean thoroughly, remove adhesive residue. Waterproofing does not bond to dust.
- Repair cracks and holes, level locally. See crack repair.
- Pour screed at a 1–2% fall towards the drain — before waterproofing, not after.
- Primer per the manufacturer's instructions.
- Sealing tapes at every corner and junction, and dedicated collars at penetrations.
- Two cross-directional coats, with full drying time between them.
- A 24-hour flood test.
- Only then — tiling.
The flood test
This is the most important check in the room and it costs almost nothing. Seal the drain, fill the floor with two to three centimetres of water, mark the water line and leave it 24 hours. A drop in the line, or a stain in the flat below, means the waterproofing failed and must be fixed now — while it costs a day's work rather than thirty thousand shekels.
Ask for the test to be documented in dated photographs. A contractor who refuses to run a flood test is telling you something.
Signs the existing waterproofing has failed
- A stain or peeling paint on the ceiling below, or on the far side of the adjoining wall.
- Dark or crumbling joints along the bottom of the shower enclosure.
- A hollow sound when a tile is tapped — a sign of debonding, usually from trapped moisture.
- A musty smell that does not clear with cleaning and ventilation.
Full diagnosis — moisture repair.
FAQ
What does bathroom waterproofing cost?
Priced separately, roughly ILS 180 to 350 per square metre depending on method — usually ILS 1,500 to 3,500 for a room. It is the cheapest item in the renovation and the most expensive one to get wrong.
Can it be done without removing the tiles?
There are clear coatings meant to be applied over existing tiles. They are a temporary way to slow a problem, not waterproofing. Real waterproofing sits under the tile by definition.
How long do you wait after waterproofing?
48 to 72 hours to full cure before tiling, depending on product, temperature and humidity. This is the time a rushed contractor shortens, and it is the most common cause of failure.
How we work
At Bramy Group waterproofing is applied in two cross-directional coats with corner tapes, and the flood test is documented and handed to the client before tiling. Part of every shower renovation and of our sealing works. Get in touch.