Tracked access platforms are incredibly versatile, but they are not magic. They are precision machines that require specific conditions to operate safely. Unfortunately, many hire projects end up stalled on day one because of minor oversights during the initial site survey.
A failed hire is expensive—you still pay for transport, machine hire, and your crew is left standing around. Here are the five most common site survey mistakes I see in the field, and how you can avoid them.
Mistake 1: Confusing Travel Slope with Setup Slope
Many spider lifts can climb steep inclines of up to 30% (around 16.7 degrees) because of their low center of gravity and high-traction rubber tracks. However, they *cannot* deploy their outriggers and work on that same slope.
Outriggers have maximum levelling capacities, usually between 10 and 15 degrees. If the ground slope exceeds this, the machine cannot level itself and will lock out. You must measure the slope *exactly* at the setup point, not just the access pathway.
Mistake 2: Forgetting the Outrigger Pad Footprint
People often measure the stowed width of a spider lift to ensure it fits through a gate, but forget to check if there is enough space to actually set it up. When the outriggers fold out, they create a wide "footprint" that is often 3m x 3m or larger.
If you are setting up in a narrow alleyway or between a wall and a flowerbed, you must check the outrigger setup dimensions. Some machines have "narrow setup" features, but this usually limits your outreach on the narrow side.
Mistake 3: Overlooking Tail Swing and Boom Clearances
It is a common mistake to look only at the target work area and the setup point, ignoring what happens in between. When a spider lift's turret rotates, the rear of the machine (the counterweight/turret housing) sweeps out. This tail swing can hit nearby structures, trees, or glass.
Additionally, check for overhead trees, cables, or building eaves that the boom might collide with as it telescopes upwards.
Mistake 4: Assuming Floor Loadings without Verification
Spider lifts are frequently hired to work inside shopping centers, airports, or historic buildings because they fit through doorways and are relatively light. However, "relatively light" for a construction machine still means 2.5 to 5 tonnes.
Never guess floor loading capacity. You need a structural engineer or site manager to confirm the maximum floor load capacity (in kN/m² or kg/m²), and compare this against the machine's outrigger point load, which can be concentrated over small areas. Spreader plates are nearly always required on suspended floors or tiles.
Mistake 5: Failing to Check the Access Route Surface
Just because a machine *can* drive across soft grass or mud doesn't mean you should let it. Tracked machines can churn up lawns, break block paving, and sink into soft turf, leaving the customer with an expensive ground-repair bill.
- On turf/soft soil: Use ground protection mats (like Trakmats) to distribute weight and avoid digging tracks.
- On block paving/curbs: Use rubber track guards or wooden ramps to avoid cracking brick edges.
Avoid Setup Failures
Don't risk a failed hire. I offer professional site surveys through Wilson Access to ensure you get the right machine and a safe, efficient setup.