An automatic sliding door looks like one product on a brochure, but on site it is two separate installations that happen to share a frame. The first is the sliding leaf itself, a thermally broken aluminum sliding door. The second is the powered operator: the header beam, motor, track drive, sensors and controller that make the leaf move on its own. Most of the precision, and most of the failures, live in the second part. If you plan and install the two as one job, you will under-build the operator and over-worry the leaf. This guide walks through the installation in that order, using real leaf dimensions so the numbers you hand to your operator supplier are the right ones.
A manual sliding door already works as a door: you push it, rollers run on a track, a lock holds it closed. Adding "automatic" does not change the leaf. It adds a suspended beam above the opening, a motor that pulls the leaf along the track, presence sensors that stop it hitting someone, and a controller that decides when to open and close. Treat them as two scopes from the first site visit:
Why this matters for installation: the leaf must be hung plumb, level and square so the operator has a true reference to pull against. If the leaf is out by a few millimetres, the motor fights it on every cycle and the safety sensors drift. Get the leaf right, then commission the operator against it.
Before any beam goes up, confirm the physical leaf data. These are real figures from ALPES thermally broken sliding door series, and they are the numbers your operator must be sized to carry:
| Series | Frame wall width (depth in wall) | Glass sash thickness | Single sash capacity |
|---|---|---|---|
| SL155 thermal break | Four track 155 mm | 54.5 mm | Up to 2800 mm wide by 2600 mm high, 400 kg rated rollers (20-wheel) |
| SL112 / 167 heavy duty | 112 mm (single or two track) / 167 mm (three track) | 43 mm | Single sash drive capacity up to 220 kg |
| SL126 / 182 thermal break | 126 mm (two track) / 182 mm (three track) | 55 mm | Single sash up to 2.5 m wide by 3.0 m high, about 7 square metres of daylight |
All ALPES leaf profiles are 6060-T66 aluminum at 1.8 to 2.5 mm wall thickness with PA66GF25 multi-chamber thermal break strips, and use German-spec hardware (ROTO, Winkhaus, CMECH, Wehag). None of that changes how you install the operator, but it does change the weight the operator must carry, which is the single most overlooked input in automatic door projects.
Operators are rated by the load they can suspend and pull. That load is the finished leaf, not a catalogue name. A widely used industry estimate is that glass weighs about 2.5 kilograms per square metre for every millimetre of its thickness. Take the SL126/182 panel above: a 2.5 m by 3.0 m leaf is 7.5 square metres, and with a 27A insulating glass unit (three glass lites plus cavities) the glass alone runs into the hundreds of kilograms before you add the aluminum frame, hardware and any railing option.
Two mistakes follow from ignoring this. First, buyers size the operator from the door model name and discover too late that a heavy insulated-glass panel exceeds the motor rating. Second, they confuse the leaf's own roller rating with the operator rating. The 400 kg figure on the SL155 is the leaf's running roller capacity; the operator motor that suspends and drives that same leaf is a different rating from a different supplier. Ask for both numbers in writing and confirm the operator rating exceeds the weighed leaf, not the empty frame.
A clean installation starts before the beam arrives. Confirm these on site:
The frame wall width is the depth that must sit inside the wall, and on a sliding door it is set by the track count: 112 mm for a single or two-track leaf, 126 to 155 mm for two-track and four-track builds, and up to 167 to 182 mm for three-track configurations. Build the rough opening to the exact frame dimension plus a uniform shimming and levelling clearance on each side; the clearance is not waste, it is what lets you bring the leaf plumb. A sliding door supplier can confirm the exact frame dimension and the tolerance the leaf was built to, so the opening matches the unit rather than the other way around.
The header is the steel or aluminum beam that carries the track, motor and suspended leaf. It must be anchored to a lintel rated for the total load, and it must be level within a tight tolerance, because every millimetre of beam error becomes drift in the running leaf. Mount the track to the header, set the hangers (with anti-rise fittings so the leaf cannot lift off the track), then hang the leaf as a two-person task: align the bottom guide in its floor channel, set the leaf height so it clears the finished floor evenly, and confirm verticality before locking anything. Only when the leaf runs smoothly by hand do you attach the operator drive to it.
Operators are typically belt driven, chain driven or gear driven. Belt systems are quiet and common for entrances; chain drives suit heavier leaves; gear-driven units are compact but less forgiving on alignment. Choose by weighed leaf and expected traffic, not by catalogue photo. Once the drive is coupled to the hangers, set the opening speed and the hold-open time to the site: a quiet office entrance and a mall entrance with continuous footfall want different settings, and both are adjusted here, not at the factory.
This is the section that separates an automatic door from a powered leaf. A safe installation needs presence sensors that detect a person in the path, safety edges that reverse the leaf on contact, and a breakout path so the door can be pushed open by hand in a power failure. The governing references are named standards, not blog numbers: in Europe the relevant document is EN 16005 for powered pedestrian doors, and in the United States the relevant document is ANSI/BHMA A156.10. Ask your operator supplier for the certified closing-force and presence-sensor limits for the exact unit, and verify them on site with a force gauge during commissioning.
Be clear about the boundary: a automatic sliding door leaf built by ALPES is supplied with its frame, glass, rollers and tested hardware, but ALPES is not the certifying body for the powered operator or the local authority having jurisdiction for automatic door codes. The operator supplier carries that responsibility, and the installer must confirm compliance for the specific site.
Activation devices are matched to the entrance: microwave or infrared radar for hands-free pedestrian flow, floor mats for defined approach lanes, keypads or card readers for access control, and a fire-interface input where the door must release on alarm. Commissioning ties it together: run the leaf through many open-close cycles, confirm alignment, set speeds and hold-open times, then perform the safety checks against the applicable standard, including a manual breakout test and a sensor-block reversal test. Hand over the operator manual, the maintenance schedule and the local service contact as part of the job, not as an afterthought.
| Deliverable | Leaf supplier (door factory) | Operator supplier |
|---|---|---|
| Frame, glass, rollers, lock, seals | Yes, built and tested | Receives the weighed leaf |
| Header beam, motor, drive, controller | No | Yes, rated to the leaf weight |
| Safety sensors and certification | No | Yes, to EN 16005 / ANSI A156.10 |
| Local code sign-off for powered door | No | Coordinates with installer and AHJ |
| Confirm before work starts | Why it blocks the job if missing |
|---|---|
| Weighed leaf mass (glass plus frame) | Operator cannot be sized without it |
| Lintel load rating signed by an engineer | Header and suspended leaf may exceed the wall |
| Finished floor level set and tiled | Leaf bottom clearance cannot be corrected later |
| Operator voltage and circuit confirmed | Wrong supply means a return visit and rewire |
| Applicable safety standard identified | Commissioning force limits are undefined |
Can any sliding door be made automatic?
Mechanically, a sliding leaf can accept an operator, but the operator must be rated for the weighed leaf and the opening must carry the header load. Confirm both before committing, rather than assuming the leaf name is enough.
Who is responsible for safety certification?
The operator supplier and the installing contractor, against the local standard such as EN 16005 or ANSI/BHMA A156.10. The leaf factory supplies the door, not the powered-door compliance.
Why weigh the glass separately from the frame?
Glass dominates the mass, and its weight scales with thickness and area. A slim frame can still hang a very heavy insulated-glass panel, and that panel sets the operator rating.
Is the roller rating the same as the operator rating?
No. The leaf's roller rating (for example 400 kg on the SL155) is the leaf running on its own track. The operator motor that suspends and drives it is a separate rating that must exceed the weighed leaf.
What is the biggest cause of automatic door callbacks?
A leaf that was not hung plumb and level, so the operator fights it every cycle. Getting the leaf true is the cheapest insurance against noise, drift and premature wear.
Do I need a structural engineer for the header?
Whenever the existing lintel above the opening is of unknown capacity, yes. The suspended load of beam, motor and leaf is real, and guessing the rating risks both the door and the wall.
Install an automatic sliding door as two scopes: a true, level, weighed leaf, then a properly rated and safety-commissioned operator against it. Confirm the leaf mass, the lintel rating and the applicable safety standard before the beam goes up, and keep the responsibility boundary clear between the leaf supplier and the operator supplier. Do those in order and the entrance runs quietly for years; skip one and it becomes a service call.
