Surface finish of shower trays: black vs. gun grey – what lasts longer

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Surface finish of linear shower drains: black vs. gun grey – what lasts longer and which to choose

When a customer chooses a linear shower drain, the first thing they usually pay attention to is the length and price. The surface finish, however, determines whether the drain will still look brand new after five years or become a visual problem in the bathroom. In practice, I have encountered with hundreds of orders that the choice of color and type of surface finish was an underestimated decision factor – and at the same time the most frequently discussed one in complaints.

This article focuses on the two most popular surface finishes for linear shower drains from SLEEK: mat black and gun grey (silver grey, sometimes called "gunmetal"). We compare them in terms of durability, chemical resistance, maintenance requirements, and visual longevity – that is, everything that really matters in a real bathroom.

What is PVD surface finish and why it is relevant for shower drains

Before we move on to the actual color comparison, we need to explain what forms the basis of the durability of any surface finish of modern shower drains. SLEEK drains use PVD (Physical Vapour Deposition) technology – a physical application of a thin metal layer in a vacuum chamber. This is a process in which an extremely thin but extremely hard layer of metal or ceramic is applied to a steel base in the form of atoms in a controlled vacuum environment.

Why is this better than a classic lacquer or electroplating? A PVD layer is truly an integral part of the surface – not just a film applied on top, but a chemically bonded layer with hardness close to that of ceramic. The result is:

Resistance to scratches – PVD layer achieves hardness of 1 500–3 000 HV (compare with ordinary steel ~200 HV)
Resistance to corrosion – the layer is chemically inert to common acids, bases and salts
Resistance to temperature changes – PVD withstands degradation from −50 °C to +400 °C
Eco-friendliness – free of chromium VI and other heavy metals
Thin layer – typically 0.5–5 µm, so it does not affect dimensions or gripping surfaces

The key conclusion is therefore: both color variants – black and gun grey – are made using the same technology and differ only in the composition of the applied layer, which has specific technical consequences for their behavior in practice.

From the diagram it is clear that the color layer itself is only the last thin film on a multi-layer protective structure. If this structure is applied correctly (and it is with SLEEK), the durability of both variants is high. The differences are subtle and relate to how each color optically reacts to everyday wear and tear.

Black surface finish – properties, advantages and limitations

Chemical composition and mechanical resistance

A black PVD layer is typically achieved by using titanium with nitrogen and carbon (TiCN) or chromium with nitrides (CrN with modification). The resulting layer is extremely hard – in some compositions it reaches up to 3 000 HV. This makes it resistant to mechanical damage during normal use.

In terms of chemical resistance, the black PVD layer is very resistant to:

Common cleaning agents (pH 4–10)
Calcium deposits – they do not stick as easily as on a chrome surface
Soap residues and shampoo
Hard water (up to about 400 mg/l CaCO₃)

A more problematic area are highly concentrated acids (e.g. HCl above 5 %), strong degreasers based on acetone and aggressive disinfectants with chlorine content above 200 ppm. These should never be used to clean the drain – you wouldn't do it on a chrome surface either.

How black color behaves in everyday use

Here comes the first practical insight from the field: black surface finish is visually "unforgiving". Every water spot, every grain of calcium, every drop of soap suds is immediately visible on a black surface. In areas with harder water (Bratislava, Nitra, Trnava – typically 200–350 mg/l CaCO₃), this means that without regular, truly thorough cleaning after each shower morning, the drain begins to look neglected much faster than its physical condition would suggest.

From an aesthetic point of view, however, the black surface finish is worth it: with proper maintenance, it looks absolutely elegant and suits modern bathrooms with black faucets, black mirror frames and dark tiles. Linear shower drain SLEEK 500 mm in black is for example a popular choice for design shower areas with anthracite tiles in 60×120 cm or 30×60 cm format.

Durability of black finish in real environment

With normal use (daily showering, regular cleaning with soft agents) and correct installation, the black PVD surface is able to maintain its original quality for 10–15 years without visible wear. Critical risks are:

Mechanical damage (fall of a metal object, sharp impact) – PVD layer is hard but brittle; it can peel off around the defect in case of sharp impacts
Aggressive cleaning (wire brushes, coarse abrasive powders) – these destroy even chrome, not to mention PVD
Long-term contact with chlorine vapors (e.g. pool environments, bathrooms next to a pool) – in such environments, every surface finish degrades faster

Gun grey surface finish – properties, advantages and limitations

What exactly is gun grey and how it is formed

„Gun grey" (literally „gun grey", referring to the dark grey color of steel weapons) is a surface finish that lies in the shade spectrum between anthracite and classic metallic grey. It has a characteristic „metallic" undertone to the touch, and visually looks different under various lighting conditions – under natural light it is more dark grey, under artificial lighting it can take on a bluish-grey or greenish-grey tint depending on the precise composition of the layer.

The PVD layer for gun grey is typically formed by a combination of chromium and nitrogen (CrN) or a combination of TiAlN, which has a specific technical impact: the gun grey layer is chemically even more corrosion resistant than black, because chromium nitrides have naturally lower reactivity with the acids common in bathroom environments.

Practical behavior of gun grey in the bathroom

This is a crucial difference: gun grey is much more „forgiving" in terms of daily visual maintenance. The grey shade optically hides limescale deposits, soap residues and minor water stains – simply because the contrast between the white deposits and the dark grey surface is lower than between the white deposits and the black surface.

In practice this means: in a bathroom with hard water, where the drain is cleaned once a week instead of after each shower, the SLEEK 600 mm in gun grey will look more aesthetically acceptable than the same drain in black. Not because it is physically cleaner – but because the human eye less perceives deposits of similar brightness on a grey background.

Gun grey also visually fits very well into:

Bathrooms with concrete or cement-effect tiling
Spaces with industrial design (metal, wood, exposed concrete)
Bathrooms with stainless steel faucets and matte tiles
Lighter bathrooms, where black would be too dominant
Combinations with aluminum profiles, grey showers and dark brown wooden elements

For example, SLEEK 500 mm in gun grey is a very popular choice in smaller shower cubicles 80×80 cm or 90×90 cm, where it is combined with chrome or brushed stainless steel faucets – gun grey does not look as contrasting as black, does not require such a strict monochrome intention, and the result looks harmonious despite the fact that not all bathroom elements have the same color.

Durability of gun grey in real conditions

In terms of physical durability, the gun grey PVD layer is at least as durable as black, and in many resistance tests against salt mist (CASS test, ISO 9227) it achieves slightly better results – likely due to the higher chromium content in the compound. For the average customer this means that gun grey is marginally more resistant to contact with chlorine (additives in water in areas with higher dosing) and long-term humidity.

Visual longevity is, however – and I emphasize this – subjective. A black surface finish still looks black after 10 years without damage. Gun grey still looks like gun grey after the same time. Both surfaces do not physically degrade if properly maintained. The difference is in how they look between cleanings.

Quantitative comparison: black vs. gun grey in a table

Parameter	Black (Black PVD)	Gun Grey (CrN PVD)
Coating hardness (HV)	2 000–3 000	1 800–2 500
Corrosion resistance (salt mist, hours)	≥ 240 h	≥ 300 h
Visibility of limescale deposits	High (contrast)	Medium (low contrast)
Frequency of required cleaning (hard water)	After each use / daily	1–2× weekly
Resistance to chlorinated environment	Good	Very good
Suitability for hard water (over 250 mg/l)	With effort	Comfortably
Design versatility in combinations	Requires intention	More versatile
Expected surface lifespan (with proper maintenance)	10–15 years	12–18 years

Values are approximate and are based on manufacturer technical data sheets and generally available testing standards for PVD coatings. Real lifespan depends on specific operating conditions.

Effect of water hardness on surface finish degradation

This is a topic that customers underestimate and technicians deal with repeatedly. In Slovakia, water hardness ranges from soft (Banská Bystrica, Ružomberok area – 80–120 mg/l CaCO₃) through medium (most cities – 150–250 mg/l) to hard (Bratislava, Trnava, some areas of eastern Slovakia – 280–380 mg/l). In Bratislava, for example, water hardness has long been in the range of 280–340 mg/l CaCO₃.

With hard water, there is intense deposition of calcium salts (CaCO₃) on all wet surfaces. On a black drain, these deposits form a white coating that is very visible. If not regularly removed, calcium carbonate can, in the long term, react with the PVD surface – not chemically degrading it, but mechanically: when removing hard deposits mechanically (scrubbing), the PVD surface can be damaged.

Conclusion for customers in areas with hard water is clear: if you want to save on daily cleaning or if you know that cleaning won't be a priority, gun grey is clearly the smarter choice. Black in an area with hard water will start to look neglected sooner than it physically wears out, if not wiped down regularly after showering.

When installing in walk-in shower enclosures without a bathtub (about which we write in the article Integrating a linear drain into a walk-in shower without a bathtub), this issue is even more acute, as the surface of the drain is exposed to a larger amount of water.

How the surface finish behaves during installation and during construction

The surface finish of the drain is not only at risk during operation – the phases of installation and finishing work are also critical. This is one of the topics that is not sufficiently covered in any brochure, but in practice I regularly encounter it.

During masonry and tiling work, the drain is exposed to:

Contact with cement milk (pH 12–13) – a strongly alkaline environment
Plaster and jointing compounds containing silicates
Mechanical damage during work with a chisel, angle grinder, tiling
Paints, varnishes, primer

The black surface finish is more sensitive to visual contamination in this respect – if cement milk settles on a black drain and does not dry (within 10–20 minutes), it leaves behind a white coating that is difficult to remove without acidic cleaning agents. Gun grey hides such a coating better.

The recommendation applies to both surfaces equally: cover the drain with the original protective film or at least with masking tape during the entire rough construction and tiling work. This is very important regardless of the color. In the article Step-by-step installation of a linear shower drain, we have described this procedure in detail.

Real-life scenarios: when customers regretted their choice

Scenario 1: Black in a Bratislava apartment with hard water

A customer from Petržalka chose the SLEEK 700 mm in black for a walk-in shower with a glass wall. He had dark gray concrete-effect tiles, black fixtures, and the overall design was perfect. After three months, he contacted us saying the drain looked "worn out." The problem? Hard water around 320 mg/l, cleaning once a week, no wiping after showering. The surface was physically in perfect condition – just covered with a white limescale residue.

Solution: he learned to wipe the water off the drain with a silicone squeegee after each shower, plus he used a weak vinegar solution (1:10) once a month. The drain then looked as good as on the day of installation. However, the customer admitted that if he had known about this necessary routine in advance, he would have chosen gun grey.

Scenario 2: Gun grey in a rural house with soft water

A customer from the area of Oravska Polhora (water hardness around 90 mg/l – very soft, mountain water) had doubts whether gun grey "would look outdated." She chose SLEEK 600 mm in gun grey with gray tiles. The result: after two years, the drain looks exactly the same as on the day of installation, practically without deposits, cleaned once a month, without special products. The customer is extremely satisfied, although in hindsight she says that with such water, she would have been satisfied with black as well.

Scenario 3: Black in a beauty salon

In a beauty salon with daily intensive use (5–8 shower cycles per day, various products), the black surface finish was significantly worn at the edges of the grate after one year. Reason: a sharp stainless steel grate mechanically abraded the edge of the PVD layer with every daily removal and insertion of the grate. Lesson: with intensive use, careful handling of the grate is critical, not just cleaning itself.

Cleaning and maintenance: what really works and what doesn't

A more detailed guide can be found in the article Cleaning and maintenance of the SLEEK linear shower drain, here we summarize the key differences for the two colors:

For the black surface finish:

Wipe off water with a silicone squeegee or a soft microfiber cloth after each shower – this is the golden rule
Weekly cleaning with a mild liquid cleaner (pH 6–8), apply, let it sit for 2 minutes, rinse, dry
For limescale deposits, use a weak citric acid solution (not vinegar, too aggressive) – 1 tablespoon in 500 ml of water
Never use abrasive sponges, never use soda, never use chlorine products above 200 ppm
Always wipe dry after cleaning – a wet surface visibly retains stains

For the gun grey surface finish:

The same rules apply, but the visible need for cleaning is less frequent
Monthly cleaning with a citric acid solution is sufficient for medium hardness water
The surface is less "showy" to stains – visually more forgiving
Watch out for oily deposits (hair conditioners, body oils) – they can be more visible on a gray surface than limescale stains

From the graph it is readable: with soft water, both surfaces are very similar (gun grey has a slight advantage), with medium water the difference is noticeable, and with hard water, gun grey is clearly more practical in terms of visual cleanliness without daily care.

Design combinations: what works in real bathrooms

The technical side is clear. But the finish of the drain is also a design decision, and here are a few specific combinations that I've seen work well in practice:

Black SLEEK finish works with:

Black bathroom taps from Grohe, Hansgrohe Tecturis, Ideal Standard Joy
Dark ceramic tiles (anthracite, brown, dark grey)
Forged or black bathroom accessories (towel bars, mirrors with black frames)
Black or bronze showers (rainshower)
Minimalist "black + white" design – a contrasting combination

Gun grey SLEEK finish works with:

Chromed taps (a classic combination)
Brushed stainless steel elements
Concrete, cement, and stone wall and floor coverings
Wooden bathroom elements (wooden steps, shelves)
Grey, white, and more colorful tiles
Industrial and loft-style interiors

For customers who are still planning the design of their entire bathroom, I recommend starting with the tiling and taps – you choose the drain as a complement to them, not the other way around. And if you're still undecided, gun grey is a more versatile choice, with which it's hard to "miss".

If you're interested in choosing a drain in more detail from other perspectives (not just color, but also placement, slope, length), take a look at our article How to choose a linear shower drain for your shower area.

Most frequently asked questions about SLEEK drain finishes

Is black or gun grey finish more durable?

Both are made using the same PVD technology and achieve very similar physical durability – around 10–15+ years with normal home use. Gun grey has slightly better chemical resistance to chlorinated environments due to a higher chromium content in the compound. Black has slightly higher mechanical hardness. In practice, the difference in durability is negligible – proper maintenance without aggressive cleaning agents and abrasives is key.

Can the PVD layer on the drain flake off or peel off in strips?

Properly applied PVD coating does not flake off – this is a fundamental difference from regular painting or electroplating. The PVD layer is chemically bonded to the base material. Flaking can occur only in the case of mechanical damage (sharp impact, scratching with sharp objects on the surface), and only locally at the site of injury. It is therefore not a manufacturing defect, but a result of physical damage. That's why it's important to protect the surface with a film during installation.

What happens if I use a regular bathroom cleaner on a black drain?

It depends on the specific product. Most common cleaners (Cif, Mr. Proper, Domestos for toilets – not!, Frosch, Frosch Bathroom) are safe in normal concentrations. The problem arises with concentrated chlorine-based products (Savo in full concentration, industrial disinfectants) and acidic cleaners for rust and limescale (phosphoric acid, hydrochloric acid). These can damage the PVD layer after repeated contact. Safe choice: a weak citric acid solution (1–2%) or special cleaners designed for PVD and matte surfaces.

Can I later change the drain finish if I don't like it anymore?

No, PVD finish cannot be repainted or changed after installation in a normal way. The drain would have to be removed and sent for special PVD recoating, which is economically unprofitable. Therefore, it is important to carefully consider the color choice before installation, ideally in the context of the entire bathroom design. The drain grate (the visible part) is a separate part that you can easily replace in the case of a clean stainless steel version – but colored grate versions are tied to the drain color.

Is gun grey "modern" or is it just a temporary trend?

Gun grey (gunmetal, anthracite, dark grey) is a color tone that has been continuously present in bathroom design for more than 10 years and its popularity is growing, not declining. In contrast, for example, golden and bronze tones, which came later, and we don't yet know how long they will last. Gun grey is a "safer" choice in terms of long-term design interest and also because it combines more easily with various styles and materials.

Does the choice of drain color also depend on the model length?

Technically no – the surface finish is applied equally to SLEEK 600 mm black and to the longer model. Visually, however, it is true that a larger area emphasizes the color – black on a longer drain appears more pronounced. If you have a small shower area (up to 80 cm), gun grey on a shorter drain will be a less dominant visual choice. For large walk-in showers, black on a 700–900 mm drain creates a strong design accent.

Conclusion: what to choose and how to decide

If I had to summarize everything I described above into a practical decision framework, it would look like this:

Choose black if: You have soft or medium-hard water (up to 200 mg/l), you are willing to wipe the drain after each shower, you have a thought-out black bathroom design with complementary black elements, and you want the maximum visual impact.

Choose gun grey if: You live in an area with hard water (BA, Trnava, NR and surroundings – over 250 mg/l), you prefer less demanding maintenance, you are combining it with chrome or brushed stainless steel, you want a versatile surface that matches with multiple styles, or you're not sure if other bathroom accessories will definitely be black.

Technically, both finishes are excellent and will last for decades without problems if handled properly. The difference is not in quality – it's in the daily experience with them. And that's exactly what should be your top priority when choosing.

If you're wondering what length of drain is optimal for your shower area, read the article What length of shower drain is suitable for my shower area. And if you're still deciding between a linear drain and a point drain, the answer is in the article Linear drain vs. point drain – which drain is better.

Do you have a question about this topic?

Can't decide or are you dealing with a specific situation in your home? Write to us – we're happy to help.