When you look at a furniture proposal, the material name and colour catch the eye straight away, while the thickness sits quietly in the corner as a small number. Yet a few millimetres decide whether a shelf will sag years from now, how a door sits on its hinges, and whether the piece looks heavy or refined. Thickness is not chosen by one rule; it depends on the job each part does.
Common thicknesses
Laminated chipboard and MDF are made in a range of thicknesses. In made-to-order furniture the most common carcass thicknesses are 16 and 18 mm. Thinner boards, such as 8–10 mm, are generally used for decorative elements or drawer bottoms, while thicker ones — 22, 25 mm and above — appear in worktops, long shelves and special design details. For cabinet backs, a separate thin HDF panel is widely used.
Which thicknesses a particular decor comes in depends on the manufacturer. In collections from brands such as Egger and Kronopol, a given colour may not be available in every thickness, so this is worth checking when the design is chosen.
Carcass: stiffness and fixings
The side panels of a carcass carry the door hinges, drawer runners and shelf supports. Two things matter here: the board must hold screws and cam fittings securely, and it must not bow over a tall height. For an ordinary bedside cabinet or a kitchen wall unit the standard carcass thickness is enough. For a floor-to-ceiling wardrobe, a heavy bookcase or a long modular system, thicker side panels or extra divisions are considered.
More thickness means more material for a screw to bite into, but the quality and correct placement of the fitting matter just as much. A thick board will not rescue a badly positioned connector.
Shelves: sag depends more on span than thickness
Three factors govern how much a shelf bends: the distance between supports, the load on it, and the board's thickness and material. Sag increases rapidly as span grows, so on a long shelf simply adding thickness is often not enough. More practical solutions are:
- splitting the shelf with a vertical division in the middle;
- supporting the back edge on the back panel or a hidden metal profile;
- gluing an extra strip along the front edge, which also makes the shelf look thicker;
- planning shorter bays for heavy items such as books.
In other words, for a long, heavily loaded shelf the question should be not "how many millimetres?" but "where is the support?"
Fronts: appearance and hardware
Front thickness is largely a matter of looks and technical compatibility. The depth of the hinge cup hole has to suit the thickness of the door, so very thin fronts may need special hinges. On tall doors, a thin front is also more prone to warping.
Visually, thin fronts and edges give a modern, light look, while thicker ones feel classic and solid. On routed MDF fronts, the thickness must allow for the depth of the profile.
Edge banding and visible thickness
Thickness is not only about strength; it is also a visual detail. The cut edge of the board is covered with edge banding, and that banding forms a visible line. On open shelving and bookcases the edge is always on show, so choosing banding in the same decor, or deliberately contrasting it, is a design decision.
Sometimes the chunky look people want does not require thicker board throughout. An extra strip is glued only along the front edge of a shelf or top, while the rest stays at standard thickness. The piece looks solid, but weight and material use barely increase. Conversely, when a very slim look is wanted, techniques such as bevelled edges or a hidden frame behind the front are used.
Thick board has downsides too
"Make it thick so it is strong" is not always right. Thick board adds weight, putting extra load on wall fixings and hinges in wall cabinets, and every panel eats a few more millimetres of internal space. Drawer systems are also sized to the carcass thickness, so changing it can change the whole hardware specification.
Questions worth asking when ordering: what thickness are the carcass, shelves and fronts; is extra support planned for long shelves; what is the back panel made of; and has the type of wall been taken into account for wall units?
In Zaferoglu Mebel's made-to-order furniture, built from Egger and Kronopol boards, each part's thickness is fixed in the design from its span and the weight it will carry.
