Aluminium vs Timber (Ekki) Crane Mats: A Specifier's Comparison

Start with what isn't in dispute. Ekki, or Azobe, is the hardwood specifiers reach for because it comfortably outperforms ordinary structural timber. Our own materials-comparison testing puts it at 34MPa compressive strength, 42MPa tensile strength, a modulus of elasticity of 20,000MPa and a density of 1,080kg/m³. Set that against the lower-grade oak sometimes used for lighter duty — 26MPa compressive, 24MPa tensile, a modulus of 13,000MPa and a density of 660kg/m³ — and the gap is obvious. Ekki is meaningfully stronger and around 1.5 times stiffer than oak, which is exactly why it's the species you specify when the load matters.

Set against aluminium, though, even Ekki is a different order of material. We engineer ALIMATS from 6005A aluminium alloy, with a compressive strength of 280MPa and a tensile strength of 270MPa — roughly eight times Ekki's figures in both directions — and a modulus of elasticity of approximately 69,000MPa, well over three times Ekki's 20,000MPa. That modulus figure is the one that matters most under a crane's outrigger, because it describes how much a material deflects under a given load — and a timber baulk will flex noticeably more than an aluminium mat carrying the same weight. Ekki is the right hardwood for the job among timbers. It still isn't in aluminium's league.

None of that settles the question, because strength and stiffness aren't the only things you're buying. The clearest case for timber is cost and availability — baulks are, generally speaking, the cheapest matting going, whether bought or hired, and they're stocked by ordinary timber merchants and plant hire firms right across the UK rather than sourced through a specialist manufacturing supply chain. For a genuinely short or one-off job — a single lift, a weekend's access track, a budget that simply doesn't stretch to a modular system — that isn't a minor point in timber's favour, it's often the deciding one.

The second is non-conductivity, and it's a real, specific advantage rather than a fallback argument. Timber doesn't conduct electricity, unlike aluminium or steel, which matters directly on work near live electrical apparatus or anywhere a non-conductive working surface is a stated requirement. That's a genuine niche where timber isn't the compromise — it's the safer choice, and sometimes the only one that satisfies the spec at all.

Then there's familiarity and disposability, which sound like soft points but aren't. Every groundworker and site manager already reads timber intuitively — how it behaves, how it's checked, how it's stacked — with none of the handling knowledge a patented interlocking system asks new users to learn. And at end of life, a worn-out or damaged baulk can simply be disposed of, or burned as waste timber, without any special process. That's genuinely simpler than the end-of-life path for a metal system, even one built to be inspected and redeployed rather than scrapped.

Finally, timber can be site-cut and adapted with basic tools if an odd size crops up — a saw and a tape measure will get a baulk to the length a job needs. A modular aluminium mat like ours can't be treated the same way. Cut a module down and its rating goes with it, because the geometry and the independently verified load figures apply to the module as we engineer it, not to whatever's left once someone's taken a grinder to it.

The counterweight to all of that is straightforward: timber is a natural material, and natural materials don't come with a guarantee that one piece performs like the next. Two baulks both sold as "Ekki" can vary significantly with the individual tree, the moisture content and the age, in a way our engineered aluminium alloy simply doesn't — we hold 6005A to properties that stay consistent and independently verified, batch to batch, because that's what makes it engineered rather than grown. Moisture adds a further variable: timber absorbs and releases water across its working life, which shifts both its weight and its strength over time, something a solid aluminium extrusion never has to contend with.

More seriously, timber can develop internal splits, checking or rot that never shows on the surface, so a baulk that looks perfectly sound to a site inspection can already have lost some of its rated capacity underneath. That's a genuine safety concern, and it has no real equivalent in a solid aluminium extrusion, where damage — a bend, a crack, a visible deformation — shows on the surface where it happened. A timber baulk can fail an invisible test long before it fails a visual one. That's the trade-off that comes with everything timber offers above: cheap, familiar and available, but harder to be certain of once it's been in service a while.

One limitation timber shares with steel rather than aluminium is sheer bulk. A baulk built to a size that actually matters under real crane loads is heavy, and moving it — especially once it's soaked up ground moisture and got heavier still — generally means plant, not two people with a lifting strap. That's a cost and a scheduling dependency that has to be weighed against the up-front cheapness of the material, particularly on a programme where mats need repositioning more than once.

We engineered ALIMATS around the opposite trade-off: modules from 13kg up to 48kg, built into configurations from 1.34m² to 8.07m², all handleable by two people with no heavy plant needed. That doesn't make timber the wrong choice for a job that only ever needs moving once — but on a programme where mats shift regularly, the plant booking that timber and steel both tend to require is a recurring cost worth costing properly rather than assuming away.

Reduced to something usable on site, the choice turns on duration, budget and what's actually driving the requirement. Timber makes its strongest case on short or one-off jobs where cost is the binding constraint, on any work involving live electrical apparatus or a specific need for a non-conductive surface, and for teams who want a material everyone already knows how to handle and can dispose of without a second thought when the job's done. If a baulk goes down once, for a job measured in days rather than months, timber's low up-front cost is hard to beat.

Aluminium earns its place wherever consistency and certainty matter as much as raw capability — programmes where the same rated load has to be guaranteed mat after mat, sites where mats are redeployed repeatedly and a hidden internal defect simply isn't an acceptable risk, and anywhere the absence of a telehandler makes a 48kg module a genuinely different proposition to a baulk that needs plant to shift. We rate ALIMATS to safe working loads up to 80 tonnes, independently verified with a Fellow of the Institution of Structural Engineers, we supply it on hire or purchase with 24/7 UK delivery, and we inspect, clean and check every mat before it goes out again — precisely the kind of certainty a natural material can't offer in the same way. Neither material is wrong. They're solving for different things, and the specifier who can say which is which is doing the job properly.