Installation of a linear shower drain step by step
Installation of a linear shower drain step by step – complete professional guide
The linear shower drain is now one of the most popular solutions for water drainage in modern bathrooms. It replaces traditional point drains and allows the creation of a visually clean, step-free shower area with a flat, barrier-free entrance. However, the installation of a linear drain is not a trivial task – unlike a classic point drain, it requires precise construction work, correct floor slope, and thorough waterproofing measures. A mistake in any of these phases can result in leaks, standing water in the shower area, or even moisture penetrating the floor structure.
This guide will take you through the entire installation process from the rough construction phase to the final installation of the grate – exactly as it works in practice. I base this on experience from dozens of projects where we installed linear drains in new builds and during renovations of existing bathrooms. The text includes specific dimensions, slope values, sequence of operations, and common mistakes to avoid.
1. Preparation and installation plan – what you need to resolve before the demolition hammer
Most problems with the installation of linear drains arise not during the installation itself, but even before it – during the planning phase. Before starting any work, you must answer several key questions.
Position of the drain in the shower area
A linear drain can be placed along a wall (most common), in the center of the shower, or at the entrance to the shower area. Each position has different requirements for the floor slope. When placed along a wall, a one-way slope is sufficient – the entire floor slopes toward the drain. For a central position, a two-way slope from the edges toward the drain axis is required. The most common solution we work with is a drain along the wall opposite the entrance – technically the simplest and visually the cleanest option.
Selection of the drain length
The length of the drain should correspond to the width of the shower area, or be a few centimeters shorter if the drain is embedded between two walls with an end profile. For a shower area of 80 cm width, a linear shower drain SLEEK 500 mm is sufficient. For a 90–100 cm wide area, we recommend a SLEEK 600 mm. For wider areas over 110 cm, a SLEEK 700 mm is suitable. More detailed criteria for selecting the length can be found in the article What length of shower drain is suitable for my shower area.
Position of the drain trap and connection to the sewer
The trap of the SLEEK linear drain is located at one end of the drain (so-called side trap), which is an advantage when connecting to an existing sewer connection. The drain outlet has a diameter of DN 50 (50 mm). It is crucial to ensure that the waste pipe from the trap leads downward with a minimum slope of 2 % (i.e., 2 cm height difference per meter of pipe length). If you are renovating an old bathroom with an existing waste system, check its exact position and height – sometimes it is necessary to modify the sewer connection before pouring the screed.
Check the thickness of the floor construction
This is the technically most critical point. The SLEEK linear drain has a total body height of approximately 90–100 mm (depending on the specific model), with the trap and basket occupying the lower part. The floor construction must be deep enough to embed the entire body of the drain and the trap so that the top edge (grate edge) is level with the final floor. In practice, this means: if you have a concrete slab and plan to install a screed + waterproofing + adhesive + tile, the total thickness of these layers must be at least equal to the height of the drain. Standardly, this comes to 100–120 mm from the top surface of the concrete slab to the top edge of the tile – which is usually not a problem in new builds, but is a critical factor in renovations.
2. Required tools and materials
Before starting the installation, prepare the following:
- Laser level or mason's level (at least 60 cm long)
- Tape measure, pencil, and notebook for noting heights
- Drill with mixing attachment, or a mortar mixer for screeds and concrete
- Mason's template or straightedge for leveling the screed
- Angle grinder with diamond blade for possible drain shortening or tile cutting
- Set of wrenches and torque wrench (for tightening trap connections)
- Sanitary silicone (neutral, mold-resistant) for final sealing
- Waterproofing coating and reinforcing fabric (minimum 50 g/m²)
- Sloped screed or industrial concrete C16/20
- Waste pipe PP DN 50 and fittings as needed
- Sealing ring for the trap (usually included in the drain packaging)
3. Preparation of the subfloor and rough construction work
Step 1 – Demolition of the existing floor (for renovation)
If you are renovating an existing bathroom, it is necessary to remove the tile, screed, and any insulation down to the concrete slab. At the same time, it is necessary to modify the existing sewer connection so that the trap outlet can be connected in the correct position. In older bathrooms with a central point drain, it may be necessary to move the sewer connection to the wall. This work requires cutting in concrete and should be handled by a plumber.
Step 2 – Installation of the Drain Flange and Test Position of the Drain
Before you start pouring the screed, place the drain trap in its final position – dry, without sealing. This will verify that the DN 50 drain flange fits precisely onto the waste pipe. The height of the waste pipe should be embedded deeply enough so that after placing the trap and pouring the screed, the drain remains exactly at the correct height level. Mark the position of the lower edge of the trap on the wall with a pencil – this mark will serve as a reference when pouring the screed.
At the same time, check the level of the drain: the body must lie horizontally – if the drain is uneven, water will accumulate at one end and will only drain through the trap, while the other end will remain standing water.
Step 3 – First Layer of Screed and Rough Leveling
Before pouring the screed, apply a penetrating coating to the concrete slab (standard penetrating primer based on acrylic dispersion, diluted 1:5). After the penetration has dried (approximately 2 hours), you can proceed with the screed pouring. Use a sloping screed with a minimum slope of 1.5 %, recommended 2 % (which means a 20 mm height difference per meter). For a 90 cm deep shower, the minimum slope from the back wall to the drain is 13.5 mm – in practice, it is better to calculate with 18–20 mm.
Do not permanently install the drain body at this stage – only temporarily insert it as a height template, align it to the level, and pour the first thick layer of screed around it. The drain must be protected with a protective film or sealed with tape in this phase to prevent material from getting into it.
4. Waterproofing – the most important step that cannot be skipped
Waterproofing is absolutely critical. In practice, I encounter cases where the previous craftsman skipped or did the waterproofing incorrectly – and after 2–3 years, moisture appears under the floor, in the ceiling of the neighbor, or in the wall structure. Proper waterproofing under a linear drain must be applied over the entire floor area of the shower and extended at least 15–20 cm up the walls.
Application procedure for waterproofing
Apply the first layer of waterproofing coating (a base-coat waterproofing on a dispersion or polyurethane base). After the first layer has dried (usually 1–2 hours according to the manufacturer), insert a sealing strip (corner profile) into the corners between the wall and the floor, which ensures elastic sealing of possible structural movements. Then apply the second layer of waterproofing, into which a reinforcing mesh is embedded. After it dries, apply the third, final layer of coating.
In the area where the drain passes through the waterproofing layer, it is necessary to use a sealing strip or sealing gasket from the drain package – precisely this base (edge of the drain body, where it sits on the floor) must be waterproofed and connected to the full-surface floor waterproofing. If this connection is not done correctly, a point is created through which water can penetrate directly next to the trap without being captured by the drain.
5. Installation of the Drain – Precise Procedure
Step 4 – Final Installation of the Trap and Connection to the Drainage
After the waterproofing layers have hardened (minimum 24 hours, ideally 48 hours at higher temperatures), you can proceed with the final installation. The SLEEK drain trap is supplied as a separate unit – remove it from the drain body (simple sliding out), slide it onto the DN 50 drainage connection, and tighten the coupling. The sealing must be dry and clean, without any residue of screed or dirt.
After connecting the trap, perform a leak test: plug the trap outlet with a stopper and pour water into the drain body. Wait 15 minutes and check if water is leaking at the joints. This is much easier to do now than after tiling the entire bathroom.
Step 5 – Installing the Drain Body and Height Adjustment
The SLEEK drain body has adjustable feet or height adjustment via screws (depending on the specific model). Set the height so that the top edge of the drain (the surface on which the grate sits) is exactly level with the final floor tiles. If you plan to use tiles with a thickness of 10 mm + adhesive mortar 6 mm, it is necessary to install the top edge of the drain 16 mm below the top edge of the leveled screed.
Checking the level is absolutely critical: place a spirit level directly on the top edge of the drain body. If the drain is not precisely horizontal, water will accumulate at the higher end. Adjust slowly and patiently – an error of 2–3 mm over a 700 mm drain will result in visible standing water.
Step 6 – Embedding and Final Sloping Screed Layer
Once the drain is in the correct position and height level, pour the second (final) layer of screed around it. Fix the drain in position – you can support it with wedges or use construction shims until the screed hardens. Make sure the screed does not enter the interior of the drain body – the inside must remain clean. Protect it with a temporary plug or paper insert.
Slope of the final sloping screed layer: minimum 1.5 %, recommended 2 %. Measurement: use a spirit level with a millimeter inclinometer or a digital slope meter (an inexpensive tool for under 20 €) and check each point of the floor. For a 80 cm deep shower with a 2 % slope, the height difference between the back wall and the drain is 16 mm. For a 120 cm deep shower, it is 24 mm. More about correct sloping can be found in the article Proper Floor Sloping for Linear Drains – How to Correctly Embed and Tile.
6. Wall Tiling and Flooring
Step 7 – Laying Tiles with Slope Direction
Tiles in the shower area are laid after the screed and waterproofing have cured. Before starting, check again that the screed surface is level within the laying tolerance (maximum deviation 3 mm under a 2 m straightedge). If irregularities are greater, level them with a thin layer of self-leveling compound.
Lay the tiles away from the drain – that is, start at the drain and proceed outward. This ensures that cut tile pieces will be at the wall (less visible) and full tiles will be at the drain. Apply the adhesive mortar using the double-coat method (mortar on the substrate and on the tiles) and ensure 100% coverage – there must be no air pockets under the tiles in the shower area, as they could absorb moisture.
Grouting: use epoxy grout or standard grout with anti-mold additives. Grout joints in the shower area should not be wider than 3–4 mm. The joint between the tiles and the drain is not filled with grout, but with sanitary silicone – this elastic connection compensates for temperature differences and possible structural movements.
Step 8 – Final Sealing of the Drain with Silicone
After grouting the tiles and the grout has hardened (minimum 24 hours), apply sanitary silicone into the joint between the drain and the tiles. The silicone must be neutral (not acetic, which smells and attacks metals), mold-resistant, and in a color matching the drain surface. For the SLEEK drain in black finish, we recommend black silicone; for the gun grey variant, a grey shade.
Before applying the silicone, clean both surfaces (the drain edge and the tiles) with isopropyl alcohol. Apply the silicone in one smooth stroke, smooth it with a wet finger or a grouting float, and immediately remove the tape. Let the silicone cure for at least 24 hours before using the shower for the first time.
7. Installation of the Grate and Final Inspection
Step 9 – Inserting the Grate and Drainage Check
The SLEEK drain grate is simply inserted or clicked into the drain body – the exact method depends on the model. Before inserting the grate, check that the inside of the drain is clean – any remaining screed, silicone, or tile fragments must be removed. Insert the trap into its place in the drain body and check that the seal fits correctly.
Final test: pour a large amount of water into the drain and observe whether it drains quickly and smoothly, whether the silicone joint leaks, and whether you can hear gurgling (a sign of insufficient slope of the waste pipe). At the same time, sprinkle water over the entire tile surface and observe whether the water quickly drains to the drain without standing.
8. Most common installation errors and how to avoid them
From practice, I know there are errors that repeat almost every other time in jobs where we repair incorrectly performed installations. Here are the most common ones:
- Insufficient or no floor slope: A classic mistake when the screed is poured "flat" without measuring the slope. Result: water stands in the shower area for minutes after showering. Solution: always measure with a digital slope meter.
- Missing or poor quality waterproofing: The second most common cause of complaints. Waterproofing must not be cut short or omitted under the pretext of saving costs. Water always finds a way – and under a linear drain, the pressure on the waterproofing is higher than on a regular floor.
- Drain not level horizontally: If the drain is sloped longitudinally (one end higher than the other), water drains only from one side and stagnates at the other end. It is necessary to measure with a spirit level directly on the drain body.
- Grid protrudes above the tile level: An unpleasant visual effect, but also a safety issue. Cause: the drain was set too high. It can only be solved by dismantling and re-setting it.
- Acetate silicone on a metal drain: Acetate silicone reacts with the surface treatment and can cause corrosion or peeling of the color finish. Always use neutral sanitary silicone.
- Trap installed without sealing or with damaged sealing: The result is a leak at the trap, which manifests as moisture under the tiles. Always check the condition of the seals during installation and replace them if in doubt.
9. Special situations and practical recommendations
Renovation – when there is not enough space for a drain
In practice, I encounter cases where the customer wants to install a linear drain in an existing bathroom with a low ceiling or a floor slab where there is not enough thickness for a standard drain. In such cases, there are solutions: some drain models have ultra-thin traps (height only 55–65 mm), or it is possible to machine a groove into the concrete slab for the trap. Therefore, always measure the available depth of the floor construction before purchasing a drain.
Installation next to a glass walk-in panel
In a walk-in shower without doors, a linear drain is almost standard. A special challenge is proper sloping to prevent water from flowing out of the shower area toward the service panel. I recommend using a miniature threshold profile or micro-threshold (height 10–15 mm) at the entrance in this case, which does not visually interfere and at the same time prevents water from escaping. More about solutions for walk-in showers can be found in the article Integrating a linear drain into a walk-in shower without a bathtub.
Choosing the color of the drain and its impact on installation
The color finish of the drain (black or gun grey) has no impact on the installation itself, but it does affect the choice of silicone and caulk. The best visual result is achieved when the silicone color matches the drain color. At the same time, it should be noted that on a black drain, unsightly seams or uneven laying are more visible. More about the differences between surface finishes can be found in the article Surface finish of a shower drain: black vs. gun grey – which lasts longer.
10. Installation schedule – realistic expectations
Many customers ask how many days the entire installation takes. The answer depends on the scope of work, but an approximate schedule for a comprehensive renovation of a shower area looks like this:
- Day 1: Demolition work, sewerage adjustment, subfloor preparation
- Day 2: First layer of screed (rough), temporary installation of the drain for height control
- Day 3–4: Curing of the screed (minimum 24 hours), application of waterproofing (2–3 layers with breaks)
- Day 5: Final installation of the drain and trap, tightness test, final sloping layer of screed
- Day 6–7: Curing of the final screed
- Day 7–9: Tiling of the walls
- Day 9–11: Tiling of the floor, grouting
- Day 12: Application of silicone, installation of the grid, final inspection
Overall, plan for 10–14 days from the start of demolition work to the commissioning of the shower area. Shortening this schedule at the expense of the curing time of materials is one of the most common causes of later problems.
11. Maintenance and long-term care after installation
Proper installation is only the beginning. To ensure a linear drain functions reliably for years, regular maintenance is necessary. The trap should be cleaned at least once every 2–3 months – depending on the intensity of use. Remove and rinse the debris basket under running water. Once a year, I recommend removing the entire trap and checking the condition of the seals.
A detailed cleaning procedure can be found in the article Cleaning and maintenance of the linear shower drain SLEEK. In case of problems with drainage or odor, also see Common faults of linear shower drains and how to eliminate them.
Frequently asked questions (FAQ)
Can I shorten the drain to the required length if the standard size does not fit?
The body of the SLEEK drain is not usually cut – models are available in lengths of 500, 600, and 700 mm, so it is possible to choose the right size for most standard shower areas. Shortening would compromise the sealing at the ends of the drain and could cause a leak. If you need a drain longer than 700 mm, it is necessary to choose another product line. If the area is smaller than 500 mm, consider a point drain – a comparison can be found in the article Linear drain vs. point drain – which drain is better.
What slope is really necessary – is 1 % enough?
Theoretically yes, 1 % is a sufficient minimum slope. In practice, however, I recommend at least 1.5 %, ideally 2 %. Reason: the floor is never perfectly smooth, tile grout creates irregularities, and at a slope of 1 %, even a small deviation in the flatness of the tiles is enough to cause water to stand. At 2 %, you have enough reserve and water drains quickly even in real conditions.
Do I need to treat the drain in any way before first use?
No, SLEEK drains have a finished surface treatment (powder coating or PVD surface) from the factory and do not require any special treatment before use. It is sufficient to rinse the drain with clean water before the first use to remove any construction dust from the installation.
What if the trap starts to smell after some time?
An odor from the trap is almost always caused by either the water seal drying out (after long periods of non-use) or by hair and soap deposits in the trap. Solution: pour 1–2 liters of water into the drain (to restore the water seal), remove and clean the basket. If the odor persists, remove the trap, clean it thoroughly, and check the seals. Details can be found in Common questions about SLEEK linear shower drains.
Can I install the SLEEK drain myself without a professional, or must I hire a contractor?
The installation of the drain itself (setting, connecting to the sewer) is manageable for a skilled DIY enthusiast. Waterproofing and screed are, however, critical phases where an error means a big problem – and a waterproofing complaint usually appears after 1–2 years, when the tiles are already laid. Therefore, I recommend entrusting these two phases to an experienced professional, while the rest can be done by yourself.
What is better: black or gun grey drain for a modern bathroom?
It depends on the overall design of the bathroom. Black is more striking and suits minimalist, industrial, or contrasting interiors. SLEEK 600 mm in gun grey looks more subtle, combines better with grey and beige tile shades, and is less prone to visible water stains and fingerprints. A detailed comparison can be found in the article Surface finish of a shower drain: black vs. gun grey – which lasts longer.
Conclusion – installation that is worth doing properly
The installation of a linear shower drain is indeed a more demanding construction process than the installation of a standard point drain, but with the right approach and by following all the steps, the result is worth it – a visually clean, functional, and hygienically trouble-free drain that will serve for decades. The key is not to underestimate the preparation, planning, sloping, and waterproofing – these are the four pillars of a successful installation. Everything else is technical routine.
If you are still choosing a trough, take a look at the full range of SLEEK linear shower troughs, including all available lengths and color finishes. If you are unsure which model is suitable for you, read the article How to choose a linear shower trough for a shower corner – you will find there complete selection criteria according to the size of the corner, design and technical requirements.
Do you have a question on this topic?
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