Concealed hinges on a filomuro invisible door

Kulttur Team · Published: 23 July 2026

On a genuine filomuro door you see no hinges at all. The leaf closes flush with the wall, and the mechanism that carries and moves it stays entirely hidden inside the frame. Concealed hinges with three-axis adjustment are the part that separates a correctly installed invisible door from one that sags, rubs or leaves an uneven reveal. Below we explain how they work, how much weight they carry and how they are adjusted, with concrete figures.

What concealed hinges are and why they matter

A concealed hinge is a knuckle that, when the door is shut, sits entirely inside the leaf and the frame. Nothing protrudes past the surface, unlike a classic surface-mounted hinge, which is visible on the edge of the leaf. On a filomuro door this is not optional: if the hinge were visible, it would break the continuous line of the wall and the whole point of an "invisible" door would be lost.

The hinge body hides in a routed pocket in the leaf and in another one in the extruded aluminium frame. The frame material is no accident: the rigidity of the aluminium profile carries the load without deforming over time, unlike HDF or timber frames, where the hinge pocket gives way under repeated stress. We covered how the materials behave differently in the article on the extruded aluminium frame versus HDF and honeycomb.

How a 3D concealed hinge works

The mechanism is made of two base plates, one fixed in the frame and one in the leaf, joined by a system of articulated arms. When you open the door, the arms unfold and let the leaf step out of the plane of the wall and swing up to 180°, without any part appearing on the visible face. When you close it, the arms fold back into the pockets.

The important part is the three-axis adjustment:

• Horizontal axis (left-right): move the leaf toward or away from the hinge to centre the side reveal.
• Vertical axis (up-down): raise or lower the leaf to even out the top and bottom reveal.
• Depth axis (front-back): push the leaf toward the wall or pull it toward you so it sits exactly flush with the finish.

Each axis has an adjustment screw reached with an Allen key, and the typical tolerance is ±3 mm in each direction. Those few millimetres are exactly the margin you need for the perimeter reveal to come out even on all sides, whatever the small deviations of the wall opening.

Direct comparison: concealed hinge vs surface hinge

Not every concealed hinge is the same, and the difference from a classic hinge shows in visibility, adjustment and capacity. The table below sums up the three categories found on interior doors.

In short: the surface hinge is cheap and robust, but it shows and limits the opening angle. The semi-concealed hinge is a compromise. The 3D concealed hinge is the only one that keeps the continuous line of the wall and offers the fine adjustment the final look depends on.

How many hinges a filomuro door needs and how much they carry

The number of hinges is set by the height and weight of the leaf, not by preference. A standard leaf with a mineral wool core and an aluminium frame weighs more than a hollow door, precisely because it is stiffer and better soundproofed.

• Leaf up to 2100 mm tall: 3 concealed hinges.
• Leaf between 2100 and 2700 mm: 4 hinges.
• Floor-to-ceiling leaf over 2700 mm: 5 hinges or more, calculated by weight.

With a capacity of 60-80 kg per hinge, a set of 3 comfortably carries an ordinary leaf, and a set of 4-5 covers very tall doors without the risk of sagging. Undersizing the number of hinges is one of the most common causes of a leaf that droops over time, along with other mistakes we gathered in the guide on common mistakes when installing a filomuro door.

Adjusting the three axes, step by step

Adjustment is done once the frame is fixed and the polyurethane foam has cured, with the leaf hung. The right order saves time:

• Step 1 — depth: bring the leaf exactly level with the wall finish, so the door face and the wall face lie in the same plane.
• Step 2 — height: raise or lower the leaf until the top reveal equals the bottom.
• Step 3 — sideways: centre the leaf between frame and wall, so the left and right reveals are identical.

The swing direction of the leaf, meaning the side on which the hinges are fitted, is decided from the start, at order time, and determines how the door opens into the room. If you are not sure which option suits you, we explained the criteria in the article on the opening direction of a filomuro door.

Are the hinges visible when the door is open?

No, or almost not at all. Even with the door open, the mechanism stays inside the pockets in the leaf and the frame. You may glimpse a small metal portion on the hinge edge of the leaf, but nothing on the visible face. That is the difference from a surface hinge, which is always visible.

How often do the hinges need adjusting?

Normally just once, at installation. After that, quality concealed hinges hold their setting for years. It is worth a check after the first heating season, when the humidity in the home changes, and perhaps a light greasing of the joints every few years so the movement stays silent.

Can the hinges carry a very tall door?

Yes, provided they are sized correctly. A floor-to-ceiling leaf uses 4-5 hinges, calculated on the real weight of the door. The rigidity of the extruded aluminium frame is essential here, because it takes the load without deforming over the height.

Can concealed hinges be replaced?

Yes. Being standardised parts mounted in routed pockets, a concealed hinge can be removed and swapped for an identical one without affecting the leaf or the frame. We do recommend calling an installer who knows the system, so the three-axis adjustment is redone correctly.

Concealed hinges are the technical heart of a filomuro door. They decide whether the wall line stays clean and whether the door moves perfectly for years. If you want to see the mechanism in person and compare the Minimal and Signature models, we look forward to seeing you at the Bucharest showroom, or you can configure the size and finish you want directly.