- Written by
- Scaffold Exchange Team
- Published
- September 26, 2026
- Reading time
- 6 min
Articulating vs telescopic
The first split is how the arm moves. An articulating boom (also called a knuckle boom or Z-boom) has two or more hinged sections, so the basket can go up, over and down the other side of an obstacle. A telescopic boom (a stick boom or S-boom) is one straight arm that extends, so it reaches further out and higher for the same machine size, but only in a straight line from the turret.
| Articulating | Telescopic | |
|---|---|---|
| Reach path | Up and over; can work behind an obstruction | Straight line from the turret |
| Horizontal outreach | Less; a 45 ft articulating reaches about 25 ft out | More; a 45 ft telescopic reaches about 38 ft out |
| Maximum platform heights | About 30 to 150 ft | About 40 to 185 ft |
| Rated load | Typically 500 lb, some to 1,000 lb | Typically 500 to 1,000 lb |
| Typical use | MEP around obstructions, façades behind landscaping, steel erection, indoor high bays | Long reach across a setback, high roofs, stadiums, bridges, industrial plants |
If you need to get past something, articulating. If you need to get far, telescopic. If the work is in the open and under about 60 ft, either will do and the supplier will send whichever is on the yard.
Electric, diesel and rough terrain
The second split is what drives it and where it can go. Electric booms run on batteries, have non-marking tyres and no exhaust, and are the choice for finished floors and enclosed spaces. They are mostly articulating, in the 30 to 45 ft range, with 60 ft models now common. Diesel and dual-fuel booms are heavier, taller and built for outdoor sites. Rough terrain models add four-wheel drive, oscillating axles and aggressive tyres; most diesel booms over 45 ft are rough terrain by default, with gradeability of 30 to 45 percent.
- Indoor, finished floor, under 45 ft: electric articulating. Check the floor load; a 45 ft electric boom weighs 13,000 to 16,000 lb.
- Outdoor, graded site, 45 to 85 ft: diesel rough terrain, articulating if there are obstructions, telescopic if not.
- Over 85 ft: large telescopic, delivered on a lowboy, needing a firm level pad and often a spotter for the tail swing.
- Hybrid machines with an engine and a battery pack exist for sites that want both; they cost more to rent.
Towable booms
A towable boom lift (trailer-mounted boom) sits on a single-axle trailer with outriggers, hitches to a half-ton pickup, and gives 34 to 55 ft of platform height for the price of a scissor. It is the standard answer for a day of work at a house, a church, a low-rise or a tree line where a self-propelled boom is more machine than the job needs. Setup is levelling the outriggers; the boom is then driven from the basket like any other.
The trade-offs are outreach and mobility. Towables are articulating with modest outreach, most carry 500 lb, and once the outriggers are down the machine does not move, so work that runs along a long façade means repeated re-setting. Weights run 3,500 to 6,000 lb, which is within a pickup's rating but worth confirming, as is the trailer light connector.
Reading a model number
Rental yards talk in model numbers, and the numbers are mostly platform height in feet with a letter for the class. Learn the two big brands' schemes and you can read a rate card.
| Model | Class | Platform height | Outreach | Notes |
|---|---|---|---|---|
| Genie Z-34/22 | Electric articulating | 34 ft | 22 ft | The workhorse indoor boom; about 10,000 lb |
| Genie Z-45 XC | Articulating (diesel or electric) | 45 ft | 25 ft | XC: 660 lb unrestricted, 1,000 lb restricted |
| JLG 450AJ | Diesel articulating | 45 ft | 24 ft | Direct competitor to the Z-45 |
| Genie S-65 XC | Telescopic | 65 ft | 56 ft | Common 60 ft class rental |
| JLG 600S | Telescopic | 60 ft | 50 ft | Same class, JLG |
| Genie S-85 XC | Telescopic | 85 ft | 76 ft | Needs a lowboy; about 39,000 lb |
| JLG 1250AJP | Articulating | 125 ft | 63 ft | Largest common articulating rental |
| Genie TZ-34/20 | Towable | 34 ft | 20 ft | About 3,700 lb; half-ton pickup |
| Genie TZ-50 | Towable | 50 ft | 29 ft | About 6,000 lb |
In Genie's scheme, Z is articulating, S is telescopic, TZ is towable, and the number is platform height; a second number is horizontal outreach. JLG uses the height plus A for articulating, S for straight (telescopic), J for a jib and P for platform rotate. Working height, which some rate cards quote, is platform height plus about 6 ft for the reach of a standing worker.
Choosing the size
- Measure the height of the work, not the building. Add nothing; platform height already assumes a worker reaching up.
- Measure how far out from where the machine can park. That is the outreach you need, and it decides articulating vs telescopic more often than height does.
- Add the tools and materials to the two people and check the rated load. Restricted and unrestricted capacities on XC-class machines differ by boom position.
- Check the path in: door widths, floor loads, overhead clearance with the boom stowed (about 7 to 8 ft on most 45 ft machines), and the turning radius.
- Ask the supplier for the machine's stowed dimensions and weight and put them in the quote request. The delivery driver will thank you.
For work that runs the length of a façade rather than a few points on it, compare the boom against a scaffold before you commit; the comparison guide walks through it, and mast climbers are the middle ground for long, tall faces. Whatever the class, every occupant of a boom basket wears a harness tied to the boom; the fall protection guide has the rule and the reasons.