A swing door looks like the simplest thing in a building, and that is exactly why people misunderstand how it works. It is not a panel that swings on its own. It is a rigid leaf held on a fixed axis by hinges, lifted against gravity by those same hinges, and held shut by a latch. Everything else you hear about — handing, self-closing, double-action, powered openers — is built on top of that one mechanism.
A swing door works because its leaf rotates about a vertical axis created by the hinges. The hinges do two jobs at once: they let the leaf turn, and they carry the entire weight of the leaf so gravity does not pull it out of the frame. A latch keeps it closed; a stop or a closer decides where it rests.
Look at a swing door as a lever. The hinges are the fixed point, or fulcrum. The handle sits as far as possible from that fulcrum, so a small push at the handle becomes enough turning force to move a heavy leaf. The heavier the leaf, the more this geometry matters for comfort and for the life of the hardware.
The hinges themselves are what keep the door from falling. They carry two kinds of load at the same time: the leaf weight pressing straight down the pin, and the pull that tries to spread the knuckles apart as the leaf swings. Smooth operation depends on keeping friction low at the knuckle — which is why better hinges use washers or bearings rather than bare metal on metal.
| Load on the door | Where it comes from | What resists it |
|---|---|---|
| Axial load (weight) | The full leaf weight pulls down the pin | The hinge pin seated in a fixed barrel |
| Radial load (spread) | The swinging leaf tries to pull knuckles apart | Leaf-to-leaf contact and the pin itself |
| Pivot friction | Knuckle interface resists smooth swing | Low-friction washers or ball bearings |
| Clearance | Gap between leaf edge and frame | Precise mortise and alignment |
Most swing doors you meet are single-acting: they swing one way against a stop and latch shut. Release the latch, push, and gravity or a closer brings them back to that one rest position.
A double-acting door — the café or butler door — has no stop and no latch. It pivots freely both ways from a centred rest plane and returns to centre on its own, using a spring or a cammed gravity pivot. That is what makes it hands-free in both directions. You cannot make a slab do this by simply hanging it on ordinary butt hinges; the hardware has to carry the weight and provide the return force at the same time.
| Property | Single-acting | Double-acting |
|---|---|---|
| Direction of swing | One way only | Both ways from centre |
| Latch | Yes, holds it shut | No latch; self-centres |
| Return force | Gravity or a closer | Spring or gravity cam |
| Best use | Rooms, entries, security | Hands-full pass-throughs |
The butt hinge is the common one: two leaves mounted on the edge of the door and the jamb, a pin through the knuckles. Cheap, simple, and right for most leaves. The pivot hinge instead puts a top and a bottom pivot on a single vertical axis — often set at or near the edge, but it can be set away from the edge. Pivots carry load on that one axis and suit heavier or taller leaves, but they demand that the top and bottom points line up on a true plumb line or the door binds.
A center swing door takes the pivot idea to the middle of the leaf rather than the edge: the axis sits at the centre, so the panel swings with equal overhang on both sides. It is a statement-entry detail, but it still rotates about a vertical axis and the load is still borne by the pivots.
Handing is decided by where you stand and which way the door swings toward you: hinges on your left means a left-hand door. Then there is inswing (hinges inside the room) versus outswing (hinges outside). Inswing is easier to weatherstrip on the head and jamb but eats interior floor space; outswing compresses the exterior seal better and is often preferred in high-wind zones, at the cost of exposed hinges that need security pins.
The latch is the part that makes a door feel like it closes. Turn the lever and a square spindle rotates inside the lockset. That rotation drives a cam which converts your twist into straight-line motion, pulling the latch bolt back out of the frame. Let go, and a small return spring pushes the bolt out again so the door reseats itself. The strike plate on the jamb is the metal anchor that catches the bolt; a properly screwed strike ties the latch into the structural jamb so a kick does not just split the wood. This is the whole reason a door clicks shut instead of bouncing open.
A big insulated-glass leaf is heavy, and the weight sets the hardware — not the look. A common industry rule is that glass weighs about 2.5 kilograms per square metre per millimetre of thickness. So a leaf 0.9 metre wide by 2.1 metres tall with 24 mm insulated glass carries roughly 0.9 × 2.1 × 30 ≈ 57 kilograms in glass alone, before the frame. That number decides whether you use two butt hinges, three, bearing hinges, or a floor pivot.
A frameless swing door pushes the glass to the very edge with almost no visible frame. The frame gets lighter, but the glass still dominates the weight budget, so hinge choice is decided by the glass, not by the minimal look. For any exterior aluminum door, the frame grade and the thermal break matter as much as the glass: a 6060-T66 profile with adequate wall thickness keeps the leaf rigid, and a PA66GF25 multi-chamber thermal break stops the aluminum from bridging heat between inside and outside.
ALPES publishes its aluminum door family as the sliding-door range. The SL155 thermal-break sliding door uses a four-track 155 mm frame, a single sash up to 2800 mm by 2600 mm, a 400 kg twenty-wheel self-balancing pulley, and passive check-valve drainage. The SL112/167 runs single, two, or three tracks with a 220 kg driving capacity and a 45 mm high-ｄｒｏｐ bottom track with an optional 85 mm water barrier. The SL126/182 is a two- or three-track lift-sliding system with 27A or 24A insulated glass. The swing-door category page exists on the site but currently lists no product.
So if your schedule calls for an aluminum swing door, the straight answer is: compare it against our sliding systems, or ask us directly whether we can build to your opening. We would rather say that than let you plan around a product we have not published. Whichever way the leaf moves, the physics above still apply — size the hinges or pivots for the leaf weight first, then choose the seals and the thermal break.
An electric swing door simply adds a powered operator on top of the manual hinge mechanism. The operator opens and closes the leaf, but the load is still carried by the hinges, so you size the hinges for the leaf first and the operator second. Treat the operator as a separate specification with its own load and power requirements.
| Symptom | Most likely cause | First fix |
|---|---|---|
| Sags at the latch side | Hinge screws pulled or too few hinges | Add a hinge or use longer screws into the jamb |
| Binds at the top | Pivot points not plumb | Re-align top and bottom pivots on a true axis |
| Self-closing slams | Spring tension too high | Lower tension; add a closer for control |
| Latch will not catch | Strike plate misaligned or worn | Re-pack the strike or shim the jamb |
| Ask for | Why it matters | Red-flag answer |
|---|---|---|
| Leaf weight with your glass | Decides hinge and pivot rating | Standard hinges with no number |
| Handing and swing direction | Decides hardware and seals | We will figure it out on site |
| Hinge type and count | The load path of the leaf | Butt hinge, unspecified |
| Thermal break type and width | Condensation and energy | Aluminum, insulated, no strip grade |
| Named hardware system | Spare parts and adjustment | German hardware as a slogan, no name |
Is a swing door the same as a pivot door?
Not quite. A pivot door uses top and bottom pivots on a central or offset axis; a butt-hinged door mounts on the edge. Both rotate about a vertical axis, but the load path and the alignment demands are different.
Why does my door sag?
The hinge load has exceeded the fixing or the hinge count. Add a hinge, or drive longer screws into the structural jamb rather than the thin frame material.
Can a swing door be glass?
Yes. The weight is set by the glass, so size the hinges to the glass weight, not to the frame.
Inswing or outswing?
It depends on clearance, weather, and egress. Outswing resists blow-in during wind but needs exterior hinge security; inswing is easier to seal inside but uses floor space.
Do I need a closer?
For fire and egress paths and self-closing requirements, often yes by code. For a home interior, it is optional and a matter of comfort.
Does ALPES make swing doors?
The published aluminum door line is sliding. The swing-door page exists but lists no product today, so ask us for a build-to-spec rather than assuming one is in the catalogue.
