Crane matting is temporary works, not just kit that gets put down
On most lifts, all the attention goes to the crane - its capacity, its radius, its rigging. The mats underneath get treated as an accessory: something ordered, delivered, laid out and then forgotten the moment the crane is set up. We think that's exactly the wrong way round.
Temporary works covers anything engineered to support a load, or to hold ground or structure in a required condition, for a defined period during construction - scaffolding, formwork, excavation support, propping, and crane pads and mats all sit inside that definition. A mat configuration under a crane's outriggers is doing precisely the same job as a piled temporary platform or a propped excavation - carrying a known load, through a known ground condition, for a defined window of time - and it has been engineered to do that safely, or it should have been.
Get it wrong and the consequence is the same class of consequence as any other temporary works failure. Misjudge the ground bearing capacity, or lay out a configuration that doesn't spread the outrigger load the way the design assumed, and the result is identical whether you call it a crane mat problem or a temporary works failure - settlement, tilt, and in the worst case an overturned crane. The label doesn't change the physics.
That's why we treat mat specification as belonging inside the same governance framework as every other temporary works item on a site, rather than something handled informally by whoever happens to be raising the order. This guide covers that framework - the roles, the checking process, the sign-off step - not the underlying calculations, which we cover in our companion guides on load-spread calculation and ground bearing capacity assessment.
Who is responsible: the roles that should own the decision
UK construction has a well-established answer to "who owns temporary works on this site", and it doesn't hinge on who happens to be free that week - and it's the answer we work to on every lift we're involved in. A competent, appointed individual - usually given the title Temporary Works Coordinator, or TWC - is responsible for making sure every temporary works item on the job, from falsework to excavation support to crane ground protection, goes through the same consistent process: someone designs it, someone checks it at a level that matches the risk, and someone signs off that it's genuinely ready before any load goes on.
On larger or more complex sites that role is often backed up by a Temporary Works Supervisor, or TWS, who puts the coordinator's procedures into practice on the ground - confirming, item by item, that what's actually installed matches what was designed before anyone allows load onto it.
Crane lifts have their own planning running alongside all of this - a lift plan and method statement covering the crane itself - and in our experience mat specification is exactly the thing that falls into the gap between the two. It gets ordered as part of the lift logistics, on a generic assumption about what a "typical" crane of that size needs, and never passes through the coordinator's process at all. The person who assesses the ground and the person who specifies the mats don't have to be one and the same, but we think the whole chain - ground data, mat design, check, sign-off - should be visible to, and owned within, the same coordination structure as every other temporary works item on the job.
| Role | Typically responsible for | Relevance to crane matting |
|---|---|---|
Temporary Works Coordinator (TWC) | Owning the temporary works process across the site or project | Ensures the mat configuration for a lift is designed, checked and signed off before the crane sets up |
Temporary Works Supervisor (TWS) | Implementing the coordinator's procedures on the ground, on larger or more complex sites | Confirms the mats installed on site match the design before load is applied |
Temporary works designer | Producing the design for a specific item | Carries out or commissions the load-spread and ground-bearing calculation for the mat configuration |
Independent checker | Reviewing a design at a level proportionate to its risk | Checks that the crane, ground and mat data used in the calculation are correct before the permit to load is issued |
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Checking the design: proportionate to risk, not one-size-fits-all
Not every temporary works design warrants the same intensity of scrutiny, and treating every case identically is itself a poor use of the process. Established UK practice is to check a design at a level proportionate to its risk and complexity - a principle rather than a fixed formula.
A routine, well-precedented setup - a familiar crane class, firm and reasonably well-understood ground, a mat configuration already used successfully in similar conditions - can usually be checked more lightly, say by another competent person reviewing the assumptions and the arithmetic. A more novel or higher-consequence setup - a heavier crane, soft or uncertain ground, sensitive buried services, an unusual configuration, or a position close to a structure that can't tolerate settlement - warrants an independent check by someone who had no hand in producing the original design. We think that separation matters, because the person who made the original assumptions is the person least likely to spot where they've gone wrong.
How many tiers of check an organisation runs internally, and what it calls them, will vary - that's a matter of each contractor's own procedures. The principle we hold to on every site is consistent: the higher the consequence of the design being wrong, the more independent the check needs to be. And that applies to a crane mat configuration exactly as it applies to a piece of temporary steelwork.
Permit to load: the sign-off before the crane sets up
Before load goes onto a temporary works item - a crane's outriggers, a piling rig, any heavy plant standing on ground protection - good practice calls for a formal sign-off step, often called a permit to load or permit to use, and we treat it as non-negotiable. Its purpose is narrow but important: to confirm that the design, the ground assessment it was based on, and what's actually been installed on site all match up, before anyone relies on them.
Applied to crane matting, that means the permit isn't satisfied just because the mats that turned up look like the right ones. It's satisfied when someone has actually confirmed that the ground under this specific pad matches the ground assessment the design used, that the configuration laid out on the ground matches the drawing, and that the crane about to load it is the one the design was calculated for.
That checkpoint matters because it's the last point at which a mismatch can be caught cheaply. Once the outriggers are down and a lift is underway, there's no chance left to notice that the ground survey was taken from a different part of the site, or that a smaller configuration was swapped in for convenience. This is also where our own independently verified capacity data earns its keep. Every ALIMATS® safe working load figure has been independently verified with a Fellow of the Institution of Structural Engineers - which is precisely the kind of independently checkable input a permit-to-load sign-off needs to be able to rely on, rather than take on trust.
Where the load-spread and ground-bearing calculations fit in
None of this replaces the underlying engineering. How a crane's outrigger load actually spreads through a mat and down into the ground is a calculation in its own right, which we set out in detail in our load-spread calculation guide. How the ground's bearing capacity is assessed, and how that capacity compares with the spread load, we cover separately in our ground bearing capacity guide.
Those calculations are inputs into the temporary works design for a given lift - not the whole of it. A correct calculation, produced by a competent person, still needs the process wrapped around it before it becomes a usable temporary works design: it needs to be recorded and dated, tied to the specific lift location it applies to, checked at a level proportionate to the risk, and finally signed off through a permit to load before anyone trusts it with a load. The arithmetic can be perfect and the design can still fail as a piece of governance if nobody has checked it, dated it, or confirmed it matches what's actually on the ground.
That's really the core distinction we're drawing here. The sibling guides answer "is this configuration strong enough". This one answers a different question - how do we know, and who has confirmed it, before we trust it with a load.
What goes wrong when the process is skipped
The failure mode that matters here usually isn't a dramatic engineering error. It's a quiet gap between what was assumed and what's actually on the ground - one that nobody was ever tasked with closing. In our experience it opens up in three places.
First, at specification: mats get ordered against a generic assumption about outrigger loads for "a crane of this size", without anyone checking that figure against the specific crane booked for the lift, or against the ground conditions actually present at the specific pad location rather than the site in general. Second, at installation: a configuration close to, but not quite matching, the design gets laid out, and because nobody was tasked with confirming installation against drawing, the discrepancy is invisible. Third, at loading: the crane sets up and the lift proceeds because the mats turned up and look broadly right, not because anyone has actually confirmed that design, ground assessment and installation all line up.
Any one of those gaps can sit there quietly for as long as the assumptions happen to hold. The trouble is that nothing in an informal process ever tests whether they hold - so the mismatch only becomes visible once load is on, at which point it shows up as settlement, tilt or worse, rather than as a finding in a check that caught it beforehand.
What to expect when crane matting is treated properly
When crane matting is being handled as the temporary works item it actually is, there's a short list of things a specifier or principal contractor should be able to see and ask for. A documented design specific to that lift and that location - not a generic spec sheet for a mat type. A named, competent person responsible for it, sitting inside the site's temporary works coordination structure rather than outside it. Evidence of a check carried out at a level appropriate to the risk of that particular lift. And a permit to load, signed off, before the crane sets up on the mats.
A mat system designed to sit cleanly inside that process makes all of this easier rather than harder, which is exactly what we built ALIMATS to do. It's a patented, modular aluminium mat system in 6005A alloy, built up from a defined configuration range - from 1.34m² to 8.07m² - with safe working loads up to 80 tonnes, comfortably covering cranes up to 150 tonnes, and every SWL figure independently verified with a Fellow of the Institution of Structural Engineers. We deliver it for hire or purchase 24/7 across the UK, built to be specified, checked and signed off against known, documented figures - rather than being an unknown quantity the process has to work around.
Whichever mat system is used, the point we'd make holds: matting under a crane is doing structural work, and it should go through the same design, check and sign-off discipline as any other temporary works item on the site - not be treated as kit that just needs to turn up.
Frequently asked questions
Does crane matting really need a formal temporary works design, or is a spec sheet enough?
A generic spec sheet tells you what a mat can carry in principle - it doesn't confirm that a specific configuration is right for a specific crane, on specific ground, at a specific location. A temporary works design does exactly that, and it's what a permit-to-load sign-off is actually checking against.
Who decides whether a mat configuration needs an independent check?
That call sits with the site's Temporary Works Coordinator, based on the risk and complexity of the specific lift - crane weight, ground uncertainty, and what's nearby. In our experience a routine, well-precedented setup usually needs a lighter check; a novel or higher-consequence one warrants an independent reviewer who had no hand in producing the original design.
What's the difference between a Temporary Works Coordinator and a Temporary Works Supervisor?
The Coordinator owns the process across the whole site or project, making sure every temporary works item is designed, checked and signed off. The Supervisor, present on larger or more complex sites, puts that process into practice on the ground, confirming installations match their designs before load goes on.
What exactly is a permit to load, and who signs it?
It's a formal sign-off, carried out before a crane or other plant is allowed to load a temporary works item, confirming the design, the ground assessment and the actual installation all match. It's typically signed by the person responsible for temporary works on that site, once they've confirmed those three things line up.
Does every single lift need its own bespoke ground-bearing calculation?
Yes - we'd expect the ground conditions at that specific pad location to be confirmed against the design's assumptions, even where a similar mat configuration has worked elsewhere on the same site. Ground conditions can vary significantly over short distances, which is exactly what the ground bearing assessment step is there to catch.
Can the same mat design be reused across multiple lifts on the same site?
Only if the ground conditions, the crane and the configuration are genuinely the same each time - and that's confirmed rather than assumed. We'd flag reuse without reconfirmation as one of the most common ways the gap between design and reality opens up unnoticed.
Who is responsible if the ground turns out to be different from what was originally assessed?
Responsibility sits with whoever within the temporary works structure signed off the permit to load, which is precisely why that step exists - to force a check of the assumptions against actual site conditions before load is applied, rather than after something has gone wrong.
Is this level of process only necessary for very large cranes?
No, and we'd push back on that assumption whenever we hear it. The governance principle - design, proportionate check, permit to load - applies regardless of crane size. What changes with crane size and ground risk is how much scrutiny the check needs, not whether the process applies at all.
How does Brilliant Ideas support this process when ALIMATS is specified?
Our ALIMATS configurations and safe working loads are documented and independently verified, which gives designers and checkers known, checkable figures to build the temporary works design and permit-to-load sign-off around - rather than starting from an unverified product claim.