An aluminium structure needs less maintenance than a coated steel one, which is one of the reasons it gets chosen, and that is exactly why the maintenance plan for one is so often missing. A short list of tasks is easy to leave out of a handover file, and a client who was told the structure is low maintenance tends not to ask for it.
The plan is worth having as a document rather than as an understanding, because the tasks are specific, the intervals matter, and several common maintenance practices actively damage the metal.
What the plan has to contain
A usable maintenance plan is not a list of tasks on its own. It needs enough context that someone who has never seen the structure can carry the work out correctly in year twenty, by which time nobody involved in the project will still be in post.
| Section | Purpose |
|---|---|
| Asset description | What it is, where, as-built refs |
| Task schedule | Work, interval, duration |
| Access method | How each task is reached |
| Materials | Cleaners, fasteners, anodes |
| Prohibitions | What must not be done |
| Records | Form and where it is kept |
The access column is the one most often omitted and the one that decides the budget, since a task requiring a closure and a platform is a different proposition from one done from the deck. Stating it turns the plan into something that can be costed rather than something that can only be intended.
The tasks that are genuinely required
Washing is first, and it is the one task with real technical justification rather than appearance. Chlorides deposited from sea spray or de-icing salt are what drive pitting, and rinsing them off with fresh water removes the driver. Annually is adequate in most environments; twice a year is sensible on a coastal site or a crossing that gets salted.
Drainage clearance follows, for the same reason it matters on any structure: standing water is the condition every corrosion mechanism prefers. Fastener checks come next, looking for missing or loosened bolts and, specifically, for white corrosion product at any point where the aluminium meets another metal.
Where the structure is in marine exposure and sacrificial anodes are fitted, their condition and replacement interval belong in the plan as a consumable with a defined life. Deck surfaces with an applied slip finish are also consumables, since the finish wears where people walk and its performance should be checked rather than assumed.
What must not be done
This section is the reason the plan needs to be a document, because every item on it is something a competent maintenance team would otherwise do without hesitation.
Alkaline and caustic cleaners. Aluminium is attacked by strong alkalis, and many industrial degreasers and concrete cleaners are strongly alkaline. A product that is entirely safe on steel will etch an aluminium surface and strip an anodised layer. Cleaning agents should be specified as neutral, and the plan should name acceptable products rather than leaving the choice to whoever is doing the work.
Steel wool and steel brushes. Abrading aluminium with a steel tool leaves iron particles embedded in the surface. Those particles rust, and each one becomes the starting point for a pit. The damage appears months later as rust staining on a metal that does not rust, and it is usually blamed on the material. Only stainless or non-metallic abrasives should be used, and they should be dedicated to aluminium rather than shared with steelwork.
Close-range pressure washing of treated surfaces. An anodic layer is hard but thin, and a lance held close enough will damage it along with any applied slip finish. The plan should give a minimum standoff and a maximum pressure rather than simply permitting washing.
Fittings added with whatever fastener is to hand. Every later addition is a new interface between aluminium and another metal, and contact with a more noble metal in a wet environment is the fastest damage mechanism the structure will meet. The plan should state the fastener specification and the isolation detail required for anything added after handover.
Repairs and modifications
Aluminium is straightforward to repair and the constraint is not the metal, it is the finish. A cut or a drilled hole in an anodised component exposes bare metal that cannot be treated on site to match, so alterations to a treated structure are visible permanently. Where later modification is likely, this should have been considered when the finish was chosen, and the plan should say so explicitly so the constraint is not discovered by someone with a drill.
Welded repair is possible and should be carried out to the same execution requirements as the original fabrication, since a weld made without the right procedure introduces a softened zone the design did not allow for. The plan should name the execution class the structure was built to so a repairer knows what they are working to.
Records, and what they are for
The plan should include the form used to record each visit and say where the completed forms are kept. This is dull and it is the only thing that makes a warranty enforceable, since most finish and coating warranties are conditional on the stated maintenance having been carried out and documented.
It also provides the trend information that turns inspection findings into decisions. A defect recorded once is a finding; the same defect measured on four visits is a rate, and a rate is what tells an owner whether to act now or at the next cycle.
What to require in the contract
Ask for the maintenance plan as a named deliverable at handover rather than as part of a general operation and maintenance file. Require it to state intervals, durations and access methods. Require the prohibited cleaning practices to be listed explicitly. Require the fastener and isolation specification for future additions. Require the execution class and as-built references to be stated.
These cost a supplier an afternoon and they are what separate a structure that reaches its design life from one that is quietly damaged by well-intentioned maintenance. How the resulting schedule feeds a budget is covered in our note on what thirty years of maintenance actually costs.
Before handover is signed off
Low maintenance is a claim about quantity, not about difficulty. The tasks on an aluminium structure are few, and two of them are things that must not be done, which no amount of general competence will supply.
Every structure we deliver is handed over with a maintenance plan built to this structure, and the documentation held by DR VERSLAS includes the as-built references a future maintainer will need long after the project team has moved on.