Open a wardrobe and you notice the shelves and the hanging rail; the back panel barely registers. Still, whether the doors keep closing evenly years later, whether the carcass stays square and how the unit is fixed to the wall all depend heavily on that panel. It is worth asking about when you order, because there are two quite different approaches and each has its own logic.
What HDF is and why it is so common
HDF is high-density fibreboard. It is related to MDF but denser and made much thinner. Furniture makers usually use a version laminated on one face, so the inside of the cabinet matches the carcass colour. Being thin, it is light, takes up very little of the internal depth and adds little to the cost.
Its job is not only to close the back. Fixed correctly, HDF gives the carcass diagonal rigidity, stopping the side panels from racking sideways like a parallelogram. In a tall wardrobe this is one of the main reasons the gaps between doors stay even over time.
The fixing method matters as much as the material
There are two main ways to fit HDF. In the first, the panel is nailed, stapled or screwed onto the rear edges of the carcass. It is simple and reliable, though the panel edge may be visible from the side. In the second, a groove is cut into the sides, bottom and top, and the HDF slides into it. The panel then sits slightly inside the carcass, a small gap is left between the cabinet and the wall, and the edges are hidden.
For a grooved back to add rigidity, the groove must be accurate and the panel must sit without play. Otherwise the HDF is just a cover and the corner joints have to carry all the load, which is why grooved systems call for particular care with the carcass fixings.
The fixing method also affects installation. Because the back locks the carcass square, a tall unit set on an uneven floor without levelling leaves the sides under tension, and the doors drift out of line with each other. Over time that tension can loosen the fixings of the HDF. Levelling the feet or plinth of a tall wardrobe is therefore a condition for the back panel to do its job. If the wall itself is out of true, the unit should not be forced against it: the gap is either closed with a decorative filler strip or allowed for at the measuring stage.
When a full-thickness back makes sense
Making the back from the same chipboard as the carcass is sometimes a technical necessity:
- Wall cabinets or shelves that will be fixed to the wall through the back itself, since thin board does not hold screws well.
- Open bookcases or display units seen from behind, for example when they stand in the room as a divider.
- Units where a TV, heavy mirror or wall panel will be mounted directly onto the back.
- Door-less units made of open niches, where the back is part of the look.
This option has a cost: the unit gets heavier, loses internal depth and takes more work to install. So a full board is usually used for particular modules rather than a whole run of cabinets.
Ventilation and wall conditions
A wardrobe standing against an external wall, especially a cold one prone to damp, should not have its back pressed flat against it. Without air movement, condensation can build up and both clothes and board can start to smell. A grooved HDF back helps here because it leaves a natural gap. Under a kitchen sink the back is often left out altogether or cut away to let pipes through.
Questions to settle when ordering
When the back panel comes up, these questions are worth asking:
- What material is the back, and what colour will it be inside?
- Is there a skirting board behind the unit, and will the back be notched for it or the carcass brought forward?
- Will it sit in a groove or be fixed on from behind?
- How will the unit be fixed to the wall, and does that suit the back panel material?
- If a socket, radiator or pipe is behind the unit, is a cut-out planned?
Zaferoglu Mebel decides between an HDF back and a full board on measuring day, once it is clear which wall the unit will stand against and what will hang from it.
