How to Pick the Right Size Class for a Tight-Access Job
Tight-access work is where compact excavators earn their reputation, and it is also where the most machine-selection mistakes are made. The reason is that access is a binary problem disguised as a spectrum. A machine that fits through the gap works; one that misses by fifty millimetres does nothing at all, no matter how capable it is in every other respect.
This is a practical procedure for choosing the right size class for a job where the machine has to get through, into or alongside something.
Measure the Constraint Before You Look at Machines
Start at the site, not at the specification sheet. There are five measurements that decide ninety per cent of tight-access selections.
- Narrowest passage. The single tightest point on the route in — a gateway, a doorway, a gap between a wall and a fence, a gap between parked vehicles. Note the true clear width, not the nominal opening.
- Overhead clearance. Low branches, cables, scaffold, garage lintels. A machine with a tall canopy may pass through a gate but not under the obstruction beyond it.
- Turning space. The area available to swing the house through a full rotation. This is the measurement most often skipped and the one that rules out the most machines.
- Ground conditions. Soft lawns, block paving, gravel and steep access all constrain machine weight and track type before they constrain size.
- Waste removal route. If spoil has to leave the same way the machine came in, the barrow or dumper width matters as much as the excavator's.
Map the Measurements to Machine Classes
| Constraint | Usually points to | Notes |
|---|---|---|
| Passage under 800 mm | Micro class, under 1 t | Check canopy height as well as width |
| Passage 800–1,100 mm | 1–1.5 t class | Variable track width is a large advantage here |
| Passage 1,100–1,500 mm | 1.5–2.5 t class | Full 360-degree swing usually available |
| Passage above 1,500 mm | 2.5–3.5 t class | Standard compact machines, more dig capacity |
| No room to swing | Zero-tail-swing machine | Tail swing type matters more than weight here |
| Soft or finished ground | Lighter machine, wider tracks | Rubber or wide pads reduce surface damage |
Use the table to find your constraint, then confirm the actual machine's published width and tail swing — not the class average. Two machines in the same class can differ by a hundred millimetres in width, which is the difference between getting through a gateway and not.
The Three Questions That Decide the Class
Once the measurements are on paper, three questions settle the selection.
Can the machine rotate on site? If there is no room for the counterweight to swing, a conventional machine is unusable regardless of its size. Zero-tail-swing designs trade some stability and lift capacity for the ability to rotate within their own footprint, which is often the whole ball game on a domestic job.
Does the small machine still do the job? This is where buyers get overconfident. A sub-one-tonne machine gets in, but it digs less per pass, lifts less and reaches less. If the job involves removing a significant volume of spoil, the number of cycles rises sharply and the day lengthens. The correct question is not "will it fit" but "will it finish the job in a sensible time once it is in there".
Can the spoil leave? A machine that fits but cannot get its spoil out of the garden is a stranded asset. Where the route is restrictive, plan spoil removal as a separate operation with a narrow dumper or wheelbarrow, and account for the extra labour in your price.
Where a Larger Machine Beats a Smaller One
There is a persistent belief that for tight access you should always choose the smallest machine that fits. That is usually wrong. If two classes both fit through the access, the larger one is normally the better commercial choice, because it completes the excavation in fewer cycles, holds grade more stably due to its greater mass, and can carry a wider bucket.
The exception is when the small machine's advantage is not size but configuration: variable track width for a narrow approach that opens out, or an extremely compact tail profile for working in a courtyard.
A Pre-Purchase Checklist
- Narrowest passage measured, including hinges and gutter lips
- Overhead clearance measured along the full route
- Turning area established; tail swing type confirmed
- Ground surface and bearing capacity assessed
- Spoil route and removal method decided
- Dig depth and reach requirement calculated from the actual job
- Accessory requirements — breaker, auger, tilt bucket — matched to auxiliary flow
- Transport route and legal towing weight checked
Machines With Variable Track Width
One configuration repeatedly solves tight-access problems that defeat fixed-width machines: variable track width. The undercarriage retracts to pass through a narrow opening and extends once through, widening the machine's footprint for stability and lifting capacity.
For a job where the approach is narrow but the working area is more generous, this single feature can move the correct choice up an entire class. Instead of buying a small machine that fits the gap but is slow on the work, you buy a slightly larger machine that squeezes through and then works at its full capacity.
The trade-offs are additional undercarriage mechanism to maintain and slightly higher weight. For contractors whose work routinely involves manoeuvring through domestic gateways, conservatories and side passages, the feature usually pays for itself on the first few jobs. Check the retracted width and the extended width separately, and confirm the machine's lift chart in both configurations — capacity differs.
Getting the Class Right
Access work rewards careful measurement and punishes guesswork. Take the five measurements, use them to narrow the class, and then buy the largest machine that genuinely fits the constraint rather than the smallest one that technically can.
The mini excavator collection lists carriers by operating weight so you can compare against your measurements directly. For typical domestic tight-access jobs, the SDLE12 mini excavator covers the lighter end of the range, while the SDLE22 mini excavator is the sensible choice when the access is generous enough to allow a larger machine and the job needs the extra reach.
