Materials and Surface Finish of Cabinets

We are still preparing products.

But you can look at other categories.

A manifold cabinet isn't just a plain sheet-metal box hung on the wall. It's a component that has to last decades, withstand moisture, cope with the mechanical stress of fitting and removing the door, and still look presentable in a flat or utility room. The choice of material and surface finish seems like a detail at first glance, but in practice it determines whether the cabinet still holds its shape and colour ten years from now, or is already rusting and cracking. In this article we look at what manifold cabinets are actually made from, what surface finishes are used, how they affect price and lifespan, and when it's worth reaching for a pricier version.

What materials are manifold cabinets made from

On the Slovak market, the vast majority of cases involve two basic material solutions - steel sheet (most often galvanised and then painted) and, to a lesser extent, plastic cabinets. Each of these solutions has its place, and it's not true that one is universally better than the other - it depends on where the cabinet is installed and how demanding the environment is.

Steel sheet - the standard for heating equipment

The vast majority of manifold cabinets commonly sold and installed here are made from steel sheet approximately 0.6 to 1.0 mm thick. This range isn't arbitrary - thinner sheet (below 0.6 mm) could flex when the manifold, valves and actuators are fitted, and would lose frame rigidity, especially in larger cabinets 600 mm wide and up. Thicker sheet above 1 mm would needlessly increase weight and price without any real benefit, since the cabinet isn't a load-bearing structure, just a cover.

The diagram above sums up exactly this rule of a sheet thickness of 0.6 to 1.0 mm - outside this range you either lose frame strength or needlessly increase the cabinet's weight and price.

Steel sheet is processed in several steps - cutting to the required size, bending into the body shape (usually with a press, so the edges are straight and free of sharp cuts), welding or riveting the corners, and finally the surface finish. It's this last stage that determines how long the cabinet lasts in real operation.

Galvanised sheet as the base

Practically all good-quality cabinets have a base of galvanised sheet (hot-dip or electro-galvanised) before the colour layer is applied. The zinc layer acts as sacrificial protection - if the top coat gets scratched somewhere and exposes the sheet, the zinc corrodes preferentially instead of the steel, protecting the structure from rust at the point of damage. Without this layer, even a small scratch during installation (for example from a screwdriver or the edge of a box) could over time lead to rusting through and rust bleeding through the paint.

Plastic cabinets - when they make sense

Plastic versions (most often ABS or polystyrene) tend to appear in smaller, simpler recessed cabinets, or in solutions offered directly by manifold manufacturers as part of a complete set. The advantage of plastic is that it doesn't corrode at all - in a high-humidity environment (for example an unheated garage, an unventilated bathroom, or near a pool) it's a practically maintenance-free solution. The downside is lower mechanical strength, worse stability at larger sizes, and less scope for later modification (for example drilling for additional pipework). Plastic is practically never used for larger manifolds with more circuits, since it couldn't bear the weight of the metal fittings and manifold without sagging.

Surface finish - powder coating

The most common surface finish for manifold cabinets on the market is powder coating. This is a technology where coloured powder is electrostatically applied to pre-galvanised, degreased sheet and then baked in an oven at around 180 to 200 °C. The result is a continuous, hard and even layer of colour that's substantially more durable than ordinary wet paint applied by spraying.

Why powder coating is better than wet paint

Mechanical durability - the baked powder layer is harder and more resistant to scratching from everyday handling of the door.
Even thickness - electrostatic application ensures that even corners and edges get an adequate layer of colour, where wet-paint spraying would risk running or a thinner layer.
UV resistance - on cabinets placed near a window or in a well-lit hallway, for example, the colour resists fading for longer.
Environmentally lighter lifespan - the technology contains no solvents, so no harmful fumes are released either during manufacturing or during any later re-sanding.

The most common shade you'll encounter on manifold cabinets is white (typically a shade close to RAL 9016 or similar traffic white), which matches white doors, tiling and most utility rooms, hallways and closets. Some manufacturers also offer painting in a different RAL shade on request, which is especially useful in architecturally designed interiors, where the cabinet is meant to be almost invisible, blending in with the wall.

Comparing material durability in practice

To get a feel for the real difference between the individual solutions, let's look at an approximate comparison of the three most common combinations of material and surface finish found in manifold cabinets - bare (unprotected) steel sheet, galvanised sheet without paint, and galvanised sheet with baked powder coating. This isn't a lab test of a specific product, but generally known technical facts about these surface finishes, which can also be verified in specialist literature on metal surface treatments.

The comparison shows why, in practice, you almost exclusively encounter the combination of galvanised sheet and powder coating - it gives the best balance of mechanical strength (which plastic lacks at larger sizes) and long-term corrosion resistance (which bare or only surface-painted sheet without a zinc layer lacks).

How a quality cabinet is made - the manufacturing process step by step

If you want to know what to look for when choosing a cabinet, it helps to understand the steps it goes through from sheet metal to finished product. Not every manufacturer follows all the steps equally rigorously, and skipping one of them (for example leaving out galvanising before painting) is exactly why cheaper cabinets of unknown origin can start to deteriorate at the edges and welds after just a few years in a utility room.

If a manufacturer skips one of these steps or does it superficially (for example insufficient degreasing before painting), the paint will over time start peeling exactly at the weld points, because powder coatings need a clean, degreased surface to adhere well. That's why it's worth buying cabinets from trusted suppliers with a clearly stated material specification, not unbranded products with no surface-finish specification at all.

How material affects the choice between surface-mounted and recessed versions

The cabinet material is also closely linked to whether it suits surface-mounting or recessed installation better. Surface-mounted cabinets made of galvanised, painted sheet are in practice the most robust solution - they hang entirely on the wall, so they have to bear their own weight, including the fitted manifold, valves and possibly actuators, without the frame twisting or the door eventually failing to close properly. That's exactly why surface-mounted cabinets almost always use thicker, more rigid galvanised sheet, since the structure isn't partly supported by the wall the way a recessed version is.

With recessed cabinets, which are mostly set directly into a wall or partition, part of the load-bearing function is taken over by the wall or the masonry recess itself, so you'll sometimes find thinner sheet construction or a plastic frame around the door. This doesn't mean lower quality - just a different way of distributing the mechanical load.

Practical recommendations by size and location

When choosing a specific cabinet, it's worth assessing material and surface finish together with size (the number of manifold circuits) and installation location. Smaller surface-mounted cabinets for up to three or four circuits usually work well even in the standard version made of galvanised, painted sheet around 0.6 mm thick, since the weight of the fitted manifold isn't high. For larger manifolds with five or more circuits, where more valves and possibly a circulation pump are also fitted into the cabinet, it's worth reaching for a larger model with a sturdier frame - here the advantage lies precisely in a proven version from an established manufacturer.

As a concrete example, we can point to three commonly available surface-mounted manifold cabinets, which differ specifically in size (and therefore in circuit capacity), while sharing the same material specification - galvanised, painted sheet - across the whole range:

Manifold cabinet 385 mm - surface-mounted - the smallest size in the range, suitable for smaller manifolds with up to three or four circuits, for example in a flat or smaller family house. Thanks to the galvanised, painted sheet it's rigid enough for everyday use even at this compact size. Price from €63.10.

Manifold cabinet 485 mm - surface-mounted - a medium size that in practice covers most family houses with a medium-sized manifold. Same material specification as the smaller model, just with more interior space for easier installation and servicing. Price from €67.53.

Manifold cabinet 615 mm - surface-mounted - the largest size in the range, designed for manifolds with a higher number of circuits, where extra space is needed for a possible circulation pump or more valves with actuators. The same galvanised and painted construction ensures sufficient rigidity even with the heavier weight of the fitted equipment. Price from €75.15.

The overview below shows how the recommended cabinet size (and therefore the amount of material used) changes depending on the number of manifold circuits - approximately according to the dimensions of the three models above:

Moisture resistance - where material really matters

Manifold cabinets are most often installed in utility rooms, closets, hallways or boiler rooms - environments where high humidity generally isn't expected. The situation changes, though, if the cabinet is located in a bathroom, an unheated garage, a basement with damper masonry, or near a washing machine and dryer, where steam condensation sometimes occurs. In such cases, a good-quality galvanised, painted cabinet has a clear advantage over cheaper solutions without a zinc layer - even if condensed moisture appears on the surface, the zinc under the paint keeps corrosion at bay for considerably longer.

If the space is extremely humid (for example right next to an unventilated shower enclosure), it's worth considering whether the cabinet can be relocated to a drier part of the flat, since no sheet-metal surface finish is designed for permanent contact with running water. This is exactly where plastic versions have their place, since they're not affected by moisture at all, though as mentioned they're better suited to smaller, simpler manifolds.

Colour and interior aesthetics

White (typically a shade close to RAL 9016) is clearly the most widespread, as it matches white doors, tiling and most bathroom cores and utility rooms. Some customers, however, look at the aesthetic side in more detail - for example if the cabinet is located in a living room or a hallway with darker doors, it's worth checking with the seller in advance whether the cabinet can be supplied in a different RAL shade, or whether the door can be repainted by arrangement with the manufacturer. Keep in mind that any additional repainting outside the manufacturing process (that is, without re-galvanising and oven-baking) will never achieve the same durability as the original powder coating, so it's worth choosing the right shade at the time of ordering.

Maintaining cabinets by material

Maintaining galvanised, painted cabinets is simple - an occasional wipe with a damp cloth and mild detergent is enough, without abrasive sponges or aggressive solvent-based cleaners that could damage the paint layer. If the surface gets mechanically scratched (for example while moving furniture or through careless handling of tools), it's recommended to treat the damaged spot as soon as possible with a thin layer of suitable touch-up paint, or at least cover it, to prevent gradual corrosion at the point where the zinc layer has been damaged.

Maintaining plastic cabinets is even simpler, since there's no risk of corrosion - wiping off dust is enough. However, watch out for the material becoming brittle at lower temperatures (for example in an unheated garage in winter), where plastic can be more prone to cracking if the door is handled carelessly.

A real-world example

A common case installation companies come across is a cabinet located in the closet of a bathroom core, where a cheap unbranded model with no clearly stated surface finish was originally fitted. After about three years in operation, the first rust spots appeared on the edges of the door and around the lock, even though the room wasn't especially humid. After replacing it with a cabinet with a proven galvanised and powder-coated finish, the same problem didn't reappear in the same location even after several years - the only difference was that the original, cheaper unit had evidently skipped the galvanising step before painting.

Summary - what to focus on when choosing material

For ordinary indoor spaces (flat, utility room, hallway), galvanised steel sheet with baked powder coating is the proven solution.
A sheet thickness of around 0.6 to 1.0 mm is enough for standard manifolds; larger versions with more circuits need a bigger, sturdier cabinet.
In damper spaces (garage, near a washing machine), the zinc layer under the paint is key for long-term corrosion resistance.
Plastic cabinets are a suitable choice only for smaller, simpler installations where high humidity outweighs the need for high mechanical rigidity.
White is the standard colour, but for more demanding architectural spaces it's worth checking in advance whether a different RAL shade is available.

Frequently Asked Questions

Is a galvanised cabinet more expensive than an ordinary painted one without a zinc layer?

The price difference between a properly galvanised cabinet and a cheaper non-galvanised one is usually not large, but the difference in lifespan is significant. Since the cabinet is fitted once and usually stays unchanged for decades, it's worth favouring a version with a declared zinc layer under the paint.

Can the cabinet be repainted a colour other than white?

Yes, both the door and the body can be repainted with ordinary metal paint, but keep in mind that a layer applied this way won't have the same durability as the original factory-baked powder coating. Before painting, the surface needs to be degreased and lightly sanded so the paint adheres well.

Will a sheet-metal cabinet hold up even in a damp garage?

A good-quality galvanised, painted cabinet handles typical garage humidity without any problems, but for permanently high humidity or direct contact with water (for example a leak), we recommend considering relocating the cabinet or consulting about a more suitable version.

Is there a difference between the material of a surface-mounted and a recessed cabinet?

Yes, surface-mounted cabinets usually use a somewhat sturdier sheet construction, since they bear the full weight of the fitted manifold on their own, without support from the wall. Recessed cabinets are partly supported by being set into the wall, so the construction can be lighter.

How can I tell a cabinet is properly galvanised before buying it?

When buying through the e-shop, it's worth checking the product description or asking the seller directly about the material specification (galvanised sheet, thickness, type of surface finish). A trustworthy seller should be able to provide this information without any problem.

Is it worth investing in a pricier cabinet just for the material?

For a product that's installed once and used for decades, the price difference between a good-quality and a below-average material specification is usually minimal compared to the cost of replacing a corroded cabinet a few years later.

Have a question about this topic?

Not sure what to choose, or dealing with a specific situation in your home? Write to us - we're happy to help.