Mobile aluminium access towers are everywhere on UK sites. They're quick to put up, easy to move, and ideal for short-duration work at height — which is precisely why they're so often misused. A tower that's missing a brace, built past its safe height, or wheeled around with someone still on the platform is one of the most common causes of serious falls in construction.
Towers fall into the same legal framework as every other work-at-height job: the Work at Height Regulations 2005. That means planning, competent people, the right equipment, and inspection — not just grabbing the nearest tower and climbing up. This guide covers what you actually need to get right.
Why towers go wrong
The problem with a mobile tower is that it looks too simple to be dangerous. People treat it like a stepladder on wheels. In reality, an incomplete or misused tower is unstable, and a fall from platform height onto a hard surface can be fatal.
The recurring failures are predictable:
- Incomplete builds — missing braces, no guardrails, gaps in the platform, or no toe boards.
- No outriggers or stabilisers when the height-to-base ratio requires them.
- Moving the tower with a person or materials on the platform.
- Building past the manufacturer's maximum height for the configuration.
- Climbing up the outside of the tower instead of using the internal ladder.
- No inspection before use or after it's been moved.
Every one of these is avoidable with a plan, the manufacturer's instruction manual, and a trained person doing the build.
Who can build a tower?
Towers must be assembled, altered and dismantled by someone competent. In practice that means PASMA training (Prefabricated Access Suppliers' and Manufacturers' Association) or an equivalent recognised scheme. A PASMA card shows the person has been trained in the correct build sequence — including the "3T" (through-the-trap) or advance guardrail method, which keeps the user protected by a guardrail before they step onto an unguarded platform.
You also need the manufacturer's instruction manual on site for the specific tower system. Towers from different manufacturers are not interchangeable — components, brace positions and maximum heights vary. Mixing components between systems is a classic cause of instability.
If you're putting together the RAMS for this work, our working at height risk assessment template walks through the hazards and controls you'll need to document, and a combined method statement sets out the safe build and use sequence.
Planning and the risk assessment
Before a tower goes up, the work needs to be planned. Your risk assessment should address:
- The ground conditions — is the surface firm, level and able to take the load? Soft ground, gradients and drain covers all affect stability.
- The required platform height and whether stabilisers or outriggers are needed.
- Overhead hazards — power lines, soffits, structural steel.
- How the tower will be accessed — always via the internal ladder, never the outside.
- How it will be moved — route, obstructions, and the rule that no one and nothing stays on the platform during a move.
- Weather — towers should not be used in high winds. Most manufacturers specify a maximum wind speed; untie or take down towers before storms.
This is the kind of task-specific document that belongs in your site paperwork alongside your method statement. If you're not sure when a written assessment is legally required, our guide on whether you need a risk assessment sets it out plainly.
Inspection: before use and every 7 days
Under the Work at Height Regulations, a tower used as a work platform must be inspected before it's first used, and then at intervals not exceeding 7 days while it remains in that position. It must also be re-inspected after any event that could affect its stability — including after it's been moved, altered, or exposed to adverse weather.
A tower inspection should confirm:
- All braces, components and platforms are fitted per the manual.
- Guardrails and toe boards are in place at the working platform.
- Wheels are locked and castors are undamaged.
- Stabilisers/outriggers are deployed where required.
- The platform is clear of damage and the trapdoor works.
- Nothing is bent, cracked or missing.
The inspection must be recorded. A tower inspection record (or scaffold inspection form) gives you a dated, signed document showing the tower was checked by a competent person — exactly what an HSE inspector or principal contractor will ask for. You'll find these in the Site Monitoring Bundle, which covers plant, access and periodic inspection forms in one purchase.
Safe use on the platform
Once the tower is up and inspected, the rules of use are simple but strict:
- Never exceed the safe working load of the platform.
- Keep guardrails and toe boards in place at all times during use.
- Don't lean out or use steps, ladders or boxes on the platform to gain extra height.
- Lock all castors before anyone climbs up.
- Move the tower by hand at the base only — never by pushing from the platform, and never with anyone on board.
- Check overhead clearance every time before moving.
Towers and the trades that use them often overlap with other access equipment. If your work also involves powered platforms, our MEWP risk assessment guide covers the pre-use checks for cherry pickers and scissor lifts, and the scaffolder pack bundles the access-trade documents together.
FAQ
Do I legally need PASMA to build a tower?
The law requires a competent person. PASMA is the recognised industry scheme that demonstrates competence for mobile towers, so in practice most principal contractors will expect a PASMA (or equivalent) card. The key point is training and the manufacturer's manual — not improvising.
How often does a mobile tower need inspecting?
Before first use, then at least every 7 days while it stays in position, and again after anything that could affect stability — being moved, altered or hit by bad weather. Record each inspection.
Can I move a tower with someone on the platform?
No. Everyone and all materials must come off before the tower is moved. Moving a loaded tower is one of the most common causes of overturning.
What's the maximum height for a mobile tower?
There's no single figure — it depends on the manufacturer's configuration, whether stabilisers or outriggers are fitted, and whether it's for indoor or outdoor use. Always follow the instruction manual for that specific tower.
Do I still need a risk assessment for a quick job on a tower?
Yes. Short-duration work still carries the risk of a serious fall. A suitable and sufficient assessment and a safe build/use method are expected regardless of how quick the task is.
Keep your tower paperwork ready
A tower is only as safe as the build, the inspection and the records behind it. Get the planning documents in place before the job, not after a near miss. The Working at Height Risk Assessment template and the Site Monitoring Bundle cover the assessment and inspection side, or if you want every template to hand all year, SafetyPod Membership gives you unlimited access for £69/year. Templates support competent people — they don't replace the training that keeps your team off the deck.