Ground Protection Mats: How Many Do You Need?
A mobile crane puts roughly 50 tonnes per square metre into the ground just driving onto site, before it lifts anything. Ground protection mats work by spreading that load over a wider area — so the question is never “are these mats strong enough” but “how much area do I need to cover”. This guide gives you the arithmetic, the rules of thumb the crane industry actually uses, and the specs that matter when buying.
The Number That Decides Everything: Ground Bearing Pressure
Ground bearing pressure is load divided by contact area. Everything about matting is an attempt to increase the denominator.
Two reference points from crane industry practice put the scale in context. A mobile crane imposes around 50 t/m² driving onto site. Meanwhile Westminster City Council in London caps ground loading on its roads at 10 t/m², while neighbouring Kensington and Chelsea allows 15 t/m². The gap between what the machine does and what the ground is permitted to take is the entire reason matting exists.
Highways-specification tarmac is typically designed for 10 to 15 t/m² and monitored, so that figure can be relied on. The danger is surfaces that look the same but are not engineered — a school playground or a retail car park may be a thin crust over uncompacted fill, and an outrigger can punch straight through with no warning.
Coverage Calculator
Enter your machine weight, the number of contact points, and your mat size. The tool works out the pressure with and without mats, and how many panels the run needs.
Why Load Rating Alone Does Not Answer the Question
Every mat is sold with a headline load rating — ours is 80 tonnes per panel. That number tells you the panel will not fail. It says nothing about whether the ground underneath will.
There is a second, less obvious point that crane pad engineers make: mats do not distribute load evenly across their full area. The harder the ground, the more it resists deflection, and the less the mat can spread the load. On concrete or asphalt, a mat may effectively transfer load through only part of its footprint. Softer ground, counterintuitively, allows better distribution.
Specification Checklist
| Spec | What to look for | Why it matters |
|---|---|---|
| Panel size | 2.4 × 1.2 m | Full lane width in one piece — fewer seams to shift or trap mud |
| Material | HDPE | Does not splinter like timber; non-conductive; recyclable at end of life |
| Tread | Hexagonal, both faces | Reversible, so the panel lasts twice as long as a single-sided mat |
| Handles | 6 cutouts around the perimeter | Two-person handling without lifting aids — the main site-safety issue |
| Connection | Side hooks | Links panels into a continuous track that will not creep apart |
| Load rating | 80 t per panel | Covers mobile cranes, excavators and delivery vehicles |
Where Mats Pay for Themselves
- Turf reinstatement avoided. Rutted grass and compacted root zones need excavation and reseeding; grass matted for a few days recovers on its own.
- No recovery costs. A machine stuck in soft ground stops the job and brings in recovery plant.
- Access in poor weather. Prolonged rain changes ground conditions; thawing frozen ground is especially deceptive because it looks far stronger than it is.
- Reusability. HDPE panels last many seasons and can be redeployed, unlike hardcore that has to be dug out and disposed of.
Common Mistakes
- Sizing on total machine weight. Load reaches the ground through a few small contact points; the per-point figure is what matters.
- Trusting a hard surface. You cannot see what is under tarmac without cutting into it.
- Forgetting the approach. Machines sink getting on and off the matted run. Extend the track past both ends.
- Assuming even distribution. On hard ground, a mat may use only part of its area — do not treat the full panel footprint as guaranteed contact.
- Ignoring the weather window. Ground assessed in dry conditions may behave completely differently after rain.
Frequently Asked Questions
How many ground protection mats do I need?
Divide the total contact area you need to cover by the area of one mat, then add one mat length at each end for the approach. A 2.4 × 1.2 m mat covers 2.88 m², so a 20 m single-lane track needs roughly 9 mats laid end to end, plus 2 for the approaches.
What ground pressure does a crane put on the ground?
Industry guidance puts a mobile crane at around 50 tonnes per square metre simply driving onto site, before any lift. That is why an unladen crane sinking on arrival is treated as a stop signal — the ground has already failed the test.
How large should an outrigger pad be?
A widely used rule of thumb is at least three times the square surface area of the outrigger shoe or float on good soil, increasing the footprint as ground conditions worsen. For any critical lift, use the crane manufacturer's published outrigger reaction forces rather than a rule of thumb.
Do ground protection mats work on tarmac and concrete?
Yes, but for a different reason. On hard surfaces the risk is not sinking but point loading and surface cracking, and you often do not know what lies under the surface. A car park or playground can look identical to a highway while being a thin layer over uncompacted fill.
Will mats stop a machine damaging grass?
They prevent rutting and root-zone compaction, which is the damage that does not recover on its own. Grass under a mat for a few days will yellow and grow back; grass that has been rutted by a tracked machine needs reinstatement.
What load rating do I need?
Match the rating to the heaviest single axle or outrigger load, not the machine's total weight, because the load reaches the ground through a small number of contact points. Our GP-2412 panel is rated to 80 tonnes, which covers most mobile cranes, excavators and delivery vehicles used on building sites.
Get a Quote
We manufacture the HDPE ground protection mat (GP-2412) direct from our factory in Tiantai, Zhejiang — 2.4 × 1.2 m panels, 80-tonne rating, hexagonal tread on both faces, MOQ 20 pieces, 22-day lead time. Send us your access run length and machine weight and we will tell you the panel count and give you a delivered price.
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