Crane hire and heavy lift are at the demanding end of outrigger pad selection. The loads are higher, the ground conditions are more variable, and the consequences of getting it wrong are more serious. This guide covers what matters most when specifying pads for crane hire and heavy lift operations.
Start With the Lift Plan
Every heavy lift should have a lift plan. The lift plan specifies the crane, the configuration, the outrigger loads at the planned radius, and the ground conditions at each outrigger position. Pad specification follows from the lift plan. You cannot select the right pad without knowing the outrigger load.
The Appointed Person is responsible for confirming that ground conditions are adequate and that outrigger pads provide sufficient load spread. Under BS 7121, this is a planning requirement, not a site decision made by the operator on the day.
Outrigger Loads in Heavy Lift
Mobile Cranes (up to 60T) →
Outrigger loads typically 10 to 30 tonnes per leg depending on boom radius and counterweight. 800mm to 1200mm pads cover most conditions. Check calculation for soft ground.
Large Mobile Cranes (60T+) →
Outrigger loads can exceed 50 tonnes per leg at extended radius. 1200mm pads or large format 2000×1200mm required. Soft ground may need modular mats or engineered solution.
All Terrain / City Cranes →
Often working in urban environments on mixed surfaces — tarmac, block paving, restricted sites. Round pads suit rotating outrigger feet. Surface protection matters as much as load spread.
Ground Conditions in Heavy Lift
Urban and construction sites present the most variable conditions. Hard standing in one outrigger position and soft fill in another. Basement slabs, underpinning, underground services. Walk every outrigger position. Do not assume the whole site is the same ground type.
If you cannot confirm the ground bearing capacity from a survey, use 50 kN/m² as a conservative assumption. A larger pad on firm ground does no harm. An undersized pad on soft ground does.
Ground Bearing Calculator
Verify any pad against your lift documentation
Select any pad from the CPS range, enter your outrigger load and ground type. Get a pass, marginal or fail result with the exact kN/m² figure for your lift documentation.
Pad Specification for Crane Hire Fleets
Most crane hire companies carry a set of pads for each crane based on the typical lift profile. For a 50 tonne mobile crane doing typical construction site work, a set of four 1200×1200×80mm square pads covers most situations on firm to soft ground. For softer ground or larger loads, the 2000×1200×100mm large format pad or modular mats provide the additional area.
Carrying one size up from the minimum is good practice. The extra weight is manageable and the extra safety margin on variable ground is worth it on every job.
Surface Protection on Sensitive Sites
UHMW-PE does not mark tarmac, concrete or block paving. Steel outrigger feet and timber packs leave marks, gouges and residue on finished surfaces. In urban environments and on commercial sites where the customer owns the surface, UHMW-PE pads protect both the ground and your relationship with the customer.
Specify the Right Pad Before the Lift
Use the Ground Bearing Calculator to verify any pad against your lift plan, or call us to discuss fleet supply for your crane hire operation.
