The structure is poured, the lift supplier arrives, and the survey finds the lift shaft is 80 mm too narrow. Now the choice is to cut concrete or change the lift. A lift shaft, the vertical enclosure the car and counterweight travel in, is the one part of a lift project you cannot easily fix later. This guide covers what the shaft, pit, overhead and elevator machine room must provide, and what to settle before construction.
Key takeaways
- Lift shaft, elevator shaft and hoistway all mean the same enclosure.
- Under EN 81-20, shaft design is the building designer's responsibility, so get the supplier's requirements early.
- Never trim pit depth or overhead height during value engineering.
- A machine room in the UAE needs independent cooling and no water pipes above it.
Lift Shaft, Elevator Shaft and Hoistway: Same Thing?
Yes. "Lift shaft" is the common UK and UAE term, "elevator shaft" is the American one, and "hoistway" is the technical word you will see in drawings. All three describe the enclosed vertical space that holds the car, guide rails, counterweight and landing doors. The pit sits at the bottom, and the overhead sits at the top.
A shaft is not a generic box. Its size depends on the lift type, the load, the door arrangement and the drive. A hydraulic lift, a traction lift and a machine-room-less (MRL) lift each ask for different dimensions. Our elevator installation team checks shaft dimensions and pit depth during the site survey, before any equipment is ordered.
Who Is Responsible for the Lift Shaft?
The building designer, in most cases. According to Elevator World's review of EN 81-20, shaft design is the responsibility of the building designer, so the architect and structural engineer must receive the lift supplier's requirements early. KONE's EN 81-20 fact sheet says the same about shaft ventilation: the standard makes it "the responsibility of the building designer."
In practice, this means the lift supplier should sign off the shaft before concrete is poured. A shaft that looks fine on the architect's plan can still fail on pit depth, overhead height or door opening width.
What a Lift Shaft Must Provide
The European standard EN 81-20 covers the construction and installation of passenger lifts. KONE's fact sheet on the standard highlights these shaft points:
- Lighting. At least 50 lux 1 m above the car roof, and at least 20 lux elsewhere in the shaft.
- Glass. Glass used in the shaft must be laminated.
- Ledges and beams. Projections wider than 150 mm must be protected so a person cannot stand on them, unless a compliant car-roof balustrade prevents access.
- Pit door. The landing door giving access to the pit must open from the shaft side, so a technician can always get out.
- Sprinklers. They may be placed in the shaft, but activation is only allowed when the lift is stationary at a landing.
The Pit and the Overhead
Technicians work in two tight places: the pit under the car and the space above it. EN 81-20 raised the bar for both.
The KONE fact sheet says the standard requires refuge spaces for technicians, with larger volumes than before. The pit's laying refuge is 0.7 x 1.0 m horizontally and 0.5 m high. A control station near the refuge space means the technician does not need a ladder or stool to reach components under the car, and pit lighting must reach 50 lux wherever a person can stand, work or move. Access rules get stricter for pits deeper than 2.5 m.
The practical lesson is that pit depth and overhead height are not numbers to trim during value engineering. Cutting them forces the supplier to change the lift or add costly workarounds. Ask the supplier for a written pit and overhead requirement for the exact model.
Already have drawings?Send them to us and we will check the shaft, pit and overhead against the lift you want, before concrete is poured.
Check My DrawingsElevator Machine Room: What It Needs
Not every lift has one. Traction lifts with a separate machine room, and many hydraulic lifts, keep the drive and controller in a dedicated room. An MRL lift places them in or beside the shaft, so there is no separate room at all. Most hydraulic lifts need a room for the pump unit and control panel, which is why planning a hydraulic lift starts with where that room will go.
If your lift has an elevator machine room, plan for these points:
- Access. KONE's fact sheet gives a minimum of 2 m high and 0.6 m wide for machine room doors that open to the shaft, and a 0.8 x 0.8 m clear passage for access trapdoors.
- Cooling. The drive and controller generate heat, and Dubai summers make it worse. A US engineering article on elevator HVAC says manufacturers commonly keep machine rooms between about 60°F and 80°F (roughly 16°C to 27°C) with 35% to 60% humidity. Its code references date from 2007, so use it as a guide and follow your lift manufacturer's range. The same article recommends that machine room cooling run independently of the building system.
- No water above or inside. The same article advises keeping water-based HVAC pipes away from the room, because a leak could be disastrous.
- Security and cleanliness. Only authorised staff should reach the room. Storage, dust and loose cables cause faults and slow down technicians.
Our elevator preventive maintenance checklist explains why machine room cooling should be checked before summer starts.
Shaft and Machine Room in New vs Existing Buildings
New buildings are simple: agree the lift type early, get the supplier's drawings, and build the shaft to them. Existing villas and buildings are harder. A lift can sometimes go into a stairwell void or a purpose-built extension, and a compact or MRL model can solve a tight space. Our guide to adding a home elevator to a Dubai villa shows the four usual retrofit positions. For high-traffic towers, see our passenger lifts.
If you are replacing an old lift in an existing shaft, the old dimensions may not meet current standards. A survey should confirm what can stay and what must change.
Shaft and Machine Room Checklist Before Construction
- Choose the lift type (hydraulic, traction or MRL) before the structure is designed.
- Obtain the supplier's shaft, pit, overhead and machine room drawings for the exact model.
- Check elevator shaft width and depth against the drawings, with the tolerance the supplier states.
- Confirm pit depth, overhead height and waterproofing, because pits sit at the lowest point and collect water.
- Plan shaft ventilation and lighting, which the designer owns.
- Place the machine room so it has safe access and cooling, away from water sources.
- Agree fire protection with the designer and the authorities.
- Ask for a site survey before concrete work starts.
How Shaft and Machine Room Care Affects Inspection
A well-built shaft makes both maintenance and inspection easier. The inspector will look at the pit, the machine room and the safety devices, and a dirty, wet or cluttered space slows everything down. Water in the pit, blocked access and a hot machine room are common reasons for repeat faults.
Keep the pit dry and clear, keep the machine room clean and cool, and fix leaks quickly. Our elevator maintenance visits include shaft, pit and machine room checks, and our elevator repair team handles faults found there.
Lift Shaft and Machine Room FAQs
What is a lift shaft?
A lift shaft is the enclosed vertical space in which the car, counterweight and guide rails travel. It is also called an elevator shaft or hoistway.
How big should a lift shaft be?
It depends on the lift type, the load and the door layout. Get the exact shaft, pit and overhead dimensions from the supplier for your chosen model, in writing.
Who builds the lift shaft?
The main contractor builds the shaft to the lift supplier's drawings, and the building designer is responsible for the design. The supplier installs the lift inside it.
Does every lift need a machine room?
No. MRL lifts place the drive and controller in or beside the shaft, so there is no separate machine room. Many hydraulic and traction lifts still need one.
How cool should an elevator machine room be?
Follow the manufacturer's range. One US engineering source reports about 16°C to 27°C with 35% to 60% humidity as common practice.
Can I install a lift in an existing building without a shaft?
Often yes, using a compact lift, a new shaft in an extension or a stairwell void. A site survey shows what fits.
Why does the pit of an elevator shaft matter so much?
Technicians work under the car, and EN 81-20 requires refuge spaces, lighting and a control station there. A pit that is too shallow, or wet, creates safety and maintenance problems.