Planning a Level-Access Shower: Falls, Waterproofing and the 2 cm Question

What level-access really means

A level-access shower, also called a flush or curbless shower, has no height difference from the rest of the bathroom. The floor runs through, and the water flows over a slight fall to a drain in the floor or on the wall. A glass screen or a projecting wall separates the shower zone visually, not by a step.

To be distinguished from this is a low-profile shower tray, which sits a few centimetres above the floor. It is quick to install and needs little height, but remains an edge. For many people that is no problem. But anyone who wants a truly continuous surface, for looks, for comfort or for old age, needs a level-access solution.

Level-access is not a question of the tile. It is a question of the centimetres underneath.

What doing nothing costs. The kerb is easy to live with when you are thirty and harder to live with later: a step with wet feet, a tray that has to be scrubbed, a door that rattles. Nothing about it is urgent, so nothing happens, until a rebuild is forced by a fall or a leak. Planning the floor now, while the bathroom is still intact, keeps every option open. So what decides it?

Build-up height: what it almost always comes down to

The drain of a shower must lie lower than the shower floor, and the waste pipe must run from there, with a fall, to the riser. On top of that come screed, waterproofing and floor covering. These layers add up to the build-up height required.

These values are a guide; the exact height depends on the system chosen. What counts is the distance to the riser. If the shower is right next to the stack, little height is often enough. If it is three metres away, the pipe becomes the bottleneck.

For Ms L., the riser was well placed, only about one metre from the planned shower. That was the first piece of good news. And once the height is found, where does the water go?

The fall: where the water goes

For water to drain away, the shower floor needs a fall. Around 1.5 to 2 per cent is usual, that is 1.5 to 2 centimetres per metre. Too little fall lets water stand; too much feels unpleasant underfoot.

Linear drain or point drain

A point drain in the middle of the shower needs a fall from all four directions. For this, the floor is divided diagonally with so-called envelope cuts. This works well with smaller formats and mosaic.

A linear drain along the wall needs a fall in only one direction. The floor remains a flat, gently sloping surface, ideal for large-format slabs. How to work with large formats in the bathroom is described in the article on large-format ceramic and grout joints.

A third option is the wall drain in a concealed installation frame. Here the drain does not sit in the floor but in the wall just above the covering. This saves height in the floor and, in an Altbau, is often the solution when things get tight. The false wall needs some depth for this, which is usually planned for the WC and taps anyway.

The direction of the fall within the room

Whether the fall lies only within the shower zone or the whole bathroom floor is slightly inclined is a design question. Usually the rest of the floor stays level, and the shower is delimited by a barely visible edge where the fall begins. With large-format slabs, this edge has to be planned precisely so that the joint layout sits cleanly. The real safeguard against leaks, though, lies underneath.

Waterproofing: the most important invisible step

A level-access shower has no tray to hold the water. The entire floor is shower surface. The waterproofing must therefore be seamless, not only in the shower but also in the adjoining areas and on the walls up to above splash height.

The waterproofing is carried out in accordance with the relevant Austrian standards for wet rooms. In practice, that means:

1. Prepare the substrate: The screed must be dry, load-bearing and clean.
2. Apply the primer: It improves the adhesion of the waterproofing.
3. Lay the sealing tapes: In all corners and at all transitions between wall and floor.
4. Fit the collars: Around pipe penetrations and tap connections.
5. Integrate the drain: The sealing flange of the drain is joined to the surface waterproofing.
6. Apply the surface waterproofing: In at least two coats, at the thickness prescribed by the manufacturer.
7. Allow to dry and test: Only then is the covering laid.

Faults in the waterproofing often show only months later, for example as a stain on the ceiling of the flat below. That is why we work here with specialist firms we know, and document the step with photographs before it disappears behind the tile. Our own joinery Tischlerkultur, a Viennese tradition since 1935, makes the vanity unit and cupboards that go with it, and one contact person coordinates every trade. And what if only two centimetres are missing?

The 2 cm question: completely flat or almost flat?

Sometimes, in the end, exactly two centimetres are missing. The question then is: does the shower still become fully level-access, with more effort, or do you accept a small edge?

In the standards for accessible building, very small height differences, in the region of 2 centimetres, are regarded as just about tolerable at door thresholds. For a shower that is also meant to be usable with a walking frame or wheelchair, however, a level transition is the safer choice. What is required in your case, for example under ÖNORM B 1600 for accessible building, we check individually.

If height is lacking, there are several routes:

• Raise the bathroom floor: The entire bathroom floor is raised. A threshold then arises at the bathroom door, which can be balanced with a ramp or an adjusted hallway floor.
• Choose a wall drain: It needs less height in the floor than a floor drain.
• Change the pipe routing: A shorter run to the riser saves fall height.
• Check the floor structure: In an Altbau, the infill can sometimes be reduced. We clarify this with the structural engineer, because sound insulation, fire protection and load-bearing capacity are affected.
• Pump as an exception: Small lifting units can actively remove the water. They are an emergency solution, because they need maintenance and make noise.

For Ms L., the wall drain and a slight raising of the whole bathroom floor by 1.5 centimetres were enough. The threshold at the bathroom door was resolved with a flat transition strip. Today the shower is fully level-access. Imagine stepping in on a cold morning: level floor under bare feet, a glass screen standing free, and no edge to think about.

The best solutions arise when the plumber, the tiler and the designer look at the floor together before anyone orders a tile.

The Viennese Altbau: Dippelbaum ceilings, timber beams and infill

Many Viennese Gründerzeit buildings have Dippelbaum or timber-beam ceilings. They are load-bearing, but not infinitely so, and they react sensitively to moisture. Above the actual ceiling there is usually an infill layer, and above that the floor build-up.

For a level-access shower this means two things. First, where infill used to lie, more height is sometimes available than you would think. Second, you cannot simply interfere with the ceiling. We clarify every change to the ceiling structure with a structural engineer and, in owner-occupied flats, additionally with the Hausverwaltung (the building management company). More on the particularities in the article on the bathroom in a Viennese Altbau, and on consents in the article on permits for conversions in an Altbau.

Material and slip resistance

A level-access shower thrives on a continuous floor. The material must therefore do two things: feel pleasant in the dry bathroom and be safe in the wet shower.

For barefoot areas, slip resistance is given in rating groups, and for shower floors medium to higher classes are usually recommended. Many ceramic manufacturers offer the same slab in a smoother version for the bathroom and a textured version for the shower. Natural stone can be brushed or textured, as described in the article on natural stone in the bathroom. Jointless solutions are also possible, with their own limits, which the article on micro-cement and trowelled finishes explains.

A made-to-measure shower floor in Cosentino Dekton is a further option. It is very resilient, jointless and can be produced with an integrated fall. More about the material can be found in Dekton explained.

Two practical points are easily overlooked in planning. First, cleaning: a linear drain collects hair and soap residue and must open without tools. Channels with a removable trap and a plain, tileable cover are the most pleasant in daily use, because you barely see them and can clean them quickly. Second, warmth: underfloor heating in the bathroom floor dries the shower area faster after showering and makes stepping out more comfortable. It too, however, needs build-up height, which must be factored into the calculation at the start.

Ms L. today showers in a shower you barely perceive as a separate zone from the entrance. The floor runs through, the glass screen stands free, and at the wall the water disappears into a narrow slot. Of the discussion about whether level-access works in an Altbau, only one sentence remains: it depends on the floor. That is why the questions below start with the height.