Under-Stairs Cupboards with Hinged Doors: Concealed Hinges for Angled Cabinet Doors

An angled concealed hinge compensates for deviating carcase geometry in under-stairs and sloping-ceiling cupboards by catering to specific degree values such as 30°, 45°, or 135°.

Building an under-stairs cupboard presents joiners and fitters with distinct geometric challenges. Because carcase sides rarely stand at a traditional 90-degree angle to one another under a sloping roof or staircase, standard off-the-shelf fittings are completely unsuitable. Planning an under-stairs unit is much like tailoring a bespoke suit – standard off-the-peg measurements simply do not fit. When the cabinet door must close flush, avoid catching on the carcase, and open sufficiently wide, selecting the exact hinge is fundamental. This guide breaks down the essential technical parameters required when choosing hinges for angled carcase constructions.

Key Buying Criteria for Angled Concealed Hinges

To guarantee the reliable operation of hinged doors on an under-stairs unit, four main technical criteria must be matched precisely to the technical drawing of the furniture.

1. Carcase Angle vs Opening Angle

The most frequent error when planning angled cupboards is confusing these two values. The carcase angle describes the angle between the side panel and the closed door. In a conventional cabinet, this is exactly 90°. In an under-stairs cupboard, however, the side panel might stand at an angle of 45° or 135° to the front. The concealed hinge must compensate for this specific carcase angle. By contrast, the opening angle merely defines how far the door can swing outward into the room when opened.

2. The Correct Cup Size

The connection between the door and the hinge is formed via the cup hole. The definitive industry standard for furniture doors from a thickness of 16 mm upwards is a 35 mm drilling diameter. The drilling depth is typically between 11.5 mm and 13 mm. For these standard dimensions, you should select 35 mm concealed hinges. The smaller 26 mm size is only used for very thin doors or in cases of extreme space constraints.

3. The Door Overlay (Mounting Type)

The position of the door relative to the carcase side when closed determines the overlay type. With a full overlay, the door covers almost the entire front edge of the carcase side panel. Full overlay concealed hinges are used for this configuration. If two doors share a single central divider, a half overlay is used, where the door covers only half of the front edge. If the door is designed to sit completely flush between the carcase sides, this is an inset door. In this case, fitters install inset concealed hinges.

4. Damping and Closing Comfort

Uncontrolled door slamming is prevented by integrated soft-close damping. The soft-close mechanism slows the door down over the final few centimetres and pulls it gently into the closed position. For modern cabinet projects, concealed hinges / cabinet hinges with damping (soft close) represent the technical benchmark.

Overview of Types and Angle Options

Geometry beneath a staircase demands specialised fittings. Depending on the carcase design, the following options are available:

• Positive angles: If the cabinet side forms an acute angle with the door, specialised hinges are required. Typical dimensions include 30-degree concealed hinges / cabinet hinges or 45-degree concealed hinges / cabinet hinges.
• Obtuse angles: If the carcase opens outwards, the angle between the closed door and the side panel is greater than 90°. For this construction, 135-degree concealed hinges / cabinet hinges are ideal.
• Wide-angle hinges: If internal drawers are planned inside the under-stairs cupboard, the door must swing completely clear of the internal opening. Hinges with an opening angle of 155° or 165° are used for this purpose. Corresponding 155-degree concealed hinges / cabinet hinges feature specialised kinematics that shift the door sideways to ensure zero protrusion.
• Standard angles: For straight sections of the under-stairs cupboard (frequently the lowest or highest carcase), standard fittings with an opening angle of approx. 110° are sufficient. For these sections, choose 110-degree concealed hinges / cabinet hinges.

Which Concealed Hinge for Which Application? (Decision Guide)

The selection of the precise hardware fitting must strictly follow the joiner's technical drawing.

If the cupboard under the stairs projects into the room and the side panel is angled at 45°... ... you will need a 45° angled hinge. This compensates for the slope of the side panel so that the door sits flush with the front line when closed.

If the under-stairs cupboard is fitted with internal drawers... ... a wide-angle hinge is essential. A standard hinge would remain in the path of the extending drawer when open. A 155° or 165° hinge swings the door entirely clear of the carcase opening, allowing the drawer's ball-bearing runners to operate without collision.

If the door is meant to sit between angled side panels... ... select an angled hinge designed for inset doors. Calculating the reveal is particularly critical here, as the door must not rub against the angled edge of the side panel during opening. Inset door concealed hinges provide the necessary adjustment range.

If the hinge lacks integrated damping but soft-close is required... ... you can retrofit the system externally. This is achieved either via clip-on dampers attached directly to the hinge arm or through separate door dampers that are drilled into the carcase side or mounted with an adapter plate.

Installation Tips for the Fitter

Installing angled hinges demands utmost precision. A deviation of just a few millimetres in angled structures will quickly lead to sticking doors or uneven gaps.

Required Tools

• Forstner bit (35 mm)
• Wood drill bit (3 mm or 5 mm for the mounting plate)
• Cordless drill/driver
• Combination square or sliding bevel
• Screwdriver (PZ2) for adjustment

Installation Steps

1. Measuring and marking out: Determine the hinge positions. For tall doors in an under-stairs cupboard (over 1600 mm), fit at least four, and for extreme heights up to five hinges to prevent door warpage. Align with the System 32 hole pattern to secure cruciform mounting plates accurately into the carcase line of holes.
2. Drilling the cup hole: Drill the holes into the door using the 35 mm Forstner bit. The depth is typically 12 mm. The distance between the drilled hole and the door edge (cup distance) usually ranges between 3 mm and 6 mm, depending on the manufacturer and the required reveal.
3. Securing the mounting plates: Screw the cruciform mounting plates firmly to the carcase side panel. Use 5 mm Euro screws (for pre-drilled lines of holes) or 3.5 mm wood screws.
4. Hanging and adjusting the door: Clip the hinge arm onto the mounting plate. Utilise the 3D adjustment (depth, height, and overlay) to align the reveal gap precisely. In angled cupboards, depth adjustment via the eccentric screw is crucial for aligning the door parallel to the angled carcase side.

FAQ – Frequently Asked Questions about Under-Stairs Cupboard Hinges

Can I use standard hinges for an under-stairs cupboard? No, not if the carcase sides are angled. A standard hinge is designed for a 90° carcase angle. With a slope of 45°, for example, the door would either fail to close or bind immediately upon opening. Specialised angled hinges must be used.

What exactly does the opening angle mean? The opening angle indicates in degrees how far a closed furniture door can swing open at maximum. A standard value for ordinary cupboards is 110°. For internal pull-outs, 155° or 165° is required.

How do I retrofit damping on angled doors? If the chosen angled hinge does not feature an integrated soft-close mechanism, you can install a standalone door damper. This is either drilled into the top or bottom panel on the handle side or surface-mounted using an adapter casing.

What cup size do I need for solid front panels on an under-stairs cupboard? For front panels made of MDF, chipboard, or solid timber with a thickness of 16 mm or more, a 35 mm cup drilling is the technical standard. This guarantees adequate stability and load transfer within the material.

What is the difference between full overlay and inset mounting on angled units? With a full overlay, the door covers the front edge of the angled carcase side. With an inset mounting, the door sits between the carcase sides, leaving the front edges of the side panels visible from the front. Both variants require fundamentally different hinge geometries on an under-stairs cupboard.

Matching Products & Categories for Your Project

To construct your under-stairs cupboard professionally, you will find suitable technical fittings across our range. Plan your hinges accurately according to your carcase angles:

• Find a full overview of all models for straight and angled constructions under concealed hinges / cabinet hinges.
• For traditional cabinet making with straight side panels, choose 90-degree concealed hinges / cabinet hinges.
• For building a robust carcase structure before mounting the doors, select precision furniture connectors.