Scaffolding and mobile tower scaffold work is among the highest-risk activity in UK construction. Falls from scaffold — both from the working platform and during erection and dismantling — account for a significant proportion of the fatal and serious injuries recorded by the HSE every year. Before any scaffold is erected, altered, or dismantled, and before any work is carried out from a scaffold platform, a suitable and sufficient risk assessment must be in place.
This guide covers the legal requirements for scaffold risk assessments in the UK, what a compliant assessment must include, the specific requirements for mobile tower scaffold, and how to produce a method statement that a principal contractor will accept.
The legal framework for scaffold risk assessments
The primary legislation governing scaffold work in the UK is the Work at Height Regulations 2005. These regulations apply to all work carried out at height — including the erection, use, alteration, and dismantling of any scaffold structure — and require that such work is properly planned, supervised, and carried out by competent persons.
The Work at Height Regulations 2005 establish a clear hierarchy for work at height:
1. Avoid work at height where reasonably practicable
2. Prevent falls using collective protective measures — including properly erected scaffold platforms with full edge protection
3. Mitigate the consequences of a fall using personal fall protection where collective measures are not reasonably practicable
For scaffold specifically, the regulations require that every scaffold structure is:
- Suitable for the purpose for which it is used
- Stable — erected on suitable ground with adequate foundations and properly tied where required
- Of sufficient strength — capable of supporting the loads placed on it
- Inspected — before first use and at regular intervals, with a written inspection record maintained
The Construction (Design and Management) Regulations 2015 (CDM 2015) reinforce these requirements. Scaffold erection, alteration, and dismantling is listed among the activities carrying particular risks in CDM 2015, and principal contractors must ensure that scaffold contractors have appropriate risk assessments and method statements in place before work starts.
The Lifting Operations and Lifting Equipment Regulations 1998 (LOLER) and the Provision and Use of Work Equipment Regulations 1998 (PUWER) also apply where scaffold components are used as part of a lifting operation or where powered access equipment is involved.
Types of scaffold covered by this guide
UK construction uses several different types of scaffold, each with its own specific risk profile:
Independent tied scaffold — the most common type of scaffold on larger construction projects. A freestanding structure tied to the building at regular intervals. Erected, altered, and dismantled by trained scaffolders, typically holding a CISRS (Construction Industry Scaffolders Record Scheme) card.
Mobile tower scaffold — a freestanding mobile scaffold structure on castors, typically used by trades carrying out work at height where a permanent scaffold is not required or proportionate. Used extensively by electricians, painters, plasterers, and maintenance trades. Erected by operatives holding a PASMA (Prefabricated Access Suppliers' and Manufacturers' Association) qualification.
Cantilever scaffold — a scaffold structure that projects outward from a building without touching the ground, typically used where ground conditions prevent standard scaffold erection.
Suspended scaffold — a platform suspended from above, used for work on building facades, bridges, and other structures where ground-based access is impractical.
System scaffold — proprietary scaffold systems such as Layher, Kwikstage, and Cuplock that use standardised components rather than traditional tube and fitting.
This guide focuses primarily on mobile tower scaffold — the type most commonly used by general contractors and trades — and the risk assessment requirements that apply to it. The principles apply equally to other scaffold types, though independent tied scaffold erection and dismantling has additional requirements and must be carried out by CISRS-qualified scaffolders.
Who can erect and use a mobile tower scaffold?
This is one of the most frequently misunderstood areas of scaffold safety in UK construction.
Mobile tower scaffold — the PASMA Code of Practice states that mobile towers should only be erected, altered, and dismantled by those who have been trained to do so. The industry-recognised qualification is the PASMA Mobile Access Tower training course. While PASMA training is not a legal requirement in the same way that some other qualifications are, it is the accepted standard of competence for mobile tower scaffold work, and most principal contractors require evidence of PASMA qualification before permitting mobile tower erection on their sites.
Independent tied scaffold — must be erected, altered, and dismantled by trained scaffolders holding a CISRS card at the appropriate level. CISRS is the industry-recognised scaffolding qualification scheme, and erection by unqualified operatives is a serious safety and legal failing.
The key principle under both the Work at Height Regulations 2005 and CDM 2015 is competence — whoever erects, uses, or dismantles scaffold must be competent to do so. Competence means having the knowledge, skills, experience, and training for the specific type of scaffold being used.
What a scaffold risk assessment must include
A compliant scaffold risk assessment for UK construction must cover the following:
1. Task and scaffold type identification
Describe specifically what is being assessed — the erection and use of a specific type of scaffold for a specific task in a specific location. "Scaffold risk assessment" is not sufficient. "Erection and use of a PASMA mobile tower scaffold for electrical first fix work on floors 2 and 3 of Unit 4" is specific enough to demonstrate genuine assessment.
2. Hazard identification
The core hazards associated with scaffold work include:
During erection and dismantling:
- Falls during erection — before guard rails are in place, operatives are exposed to unprotected edges
- Falls of materials and components — scaffold tubes, boards, and fittings dropped from height onto operatives or members of the public below
- Overturning during erection — a partially erected tower is inherently less stable than a completed one
- Manual handling — scaffold components are heavy and awkward to handle, particularly in confined spaces or on slopes
During use:
- Falls from the working platform — inadequate guard rails, damaged boards, or operatives leaning out beyond the platform edge
- Overturning — mobile towers on uneven or soft ground, or with outriggers not deployed, are at risk of overturning
- Overloading — placing excessive loads on the platform, or having too many operatives on the platform simultaneously
- Movement while occupied — mobile towers must never be moved while anyone is on the platform
- Proximity to overhead services — electricity cables, both overhead lines and cables within buildings
- Ground conditions — soft, uneven, or sloped ground affecting stability
- Weather — high winds significantly increase the overturning risk for mobile towers and should trigger suspension of work at height
Inspection and maintenance:
- Damaged components — bent or cracked tubes, damaged boards, worn castors
- Missing components — guard rails removed and not replaced, toe boards absent
3. Risk rating
Rate each hazard for likelihood and severity both before and after controls are applied. The residual risk after controls should be as low as reasonably practicable.
4. Control measures
For each hazard identified, specify the control measures in place. For mobile tower scaffold the key controls include:
Competency and training — confirm that all operatives erecting and using the mobile tower hold a valid PASMA qualification. Record the names and qualification details.
Pre-use inspection — every mobile tower must be inspected before each period of use. The inspection checks the condition of all components, the security of all connections, the condition of the working platform and boards, the deployment of outriggers where required, and the ground conditions at each base. The inspection must be recorded in writing.
Working platform specification — confirm that the working platform is fully boarded, has guard rails on all open sides (minimum 950mm high), has a mid-rail, and has toe boards (minimum 150mm high) to prevent tools and materials falling from the platform.
Outrigger deployment — for mobile towers above a certain height-to-base ratio, outriggers must be deployed to prevent overturning. The PASMA guidance specifies the height-to-base ratios for indoor and outdoor use, and outrigger requirements for each.
Ground conditions assessment — confirm that the ground is firm, level, and capable of supporting the loaded tower. Soft ground, slopes, and surfaces with drainage channels or covers require specific assessment.
Exclusion zone — establish and maintain an exclusion zone around the base of the tower during erection, dismantling, and use to protect people on the ground from falling materials.
Weather monitoring — specify the wind speed threshold at which work will be suspended. The PASMA guidance recommends suspending use of mobile towers in winds exceeding Beaufort Force 6 (approximately 25mph).
No movement while occupied — all operatives must descend from the platform before the tower is moved. This must be explicitly stated in the risk assessment and reinforced at the toolbox talk briefing.
5. Inspection record reference
Reference the pre-use inspection record as a supporting document. The written inspection record is a legal requirement under the Work at Height Regulations 2005 for any scaffold from which a person could fall more than 2 metres.
6. Assessor details, signature, and review date
Signed and dated by a competent person. The assessment must be reviewed if conditions change — new location, different ground conditions, change in task, or following any near miss or incident.
The method statement for scaffold work
A method statement for scaffold erection, use, and dismantling describes step-by-step how the work will be carried out safely. For mobile tower scaffold the method statement typically covers:
Pre-erection checks — visual inspection of all components before assembly, checking for damage, confirming the ground conditions, confirming outrigger requirements, checking overhead services.
Erection sequence — the specific sequence for assembling the tower, including at what point guard rails are installed to protect operatives during the build. PASMA's through-the-trap method requires guard rails to be installed from the level below before the next level is accessed.
Working platform specification — boards fully in place, all guard rails fitted, toe boards fitted, trap door closed when not in access use.
Use and movement — operatives descend before movement, castors unlocked for movement and locked immediately once in position, outriggers checked after each move.
Dismantling sequence — the reverse of erection, with guard rails remaining in place until the last possible point.
Emergency procedures — what to do if the tower becomes unstable, if someone falls, or if an operative becomes stuck at height.
Scaffold inspections — the legal requirements
The Work at Height Regulations 2005 require that any scaffold from which a person could fall more than 2 metres must be inspected:
- Before first use following erection or following any event likely to have affected its stability
- After any substantial addition, dismantling, or other alteration
- After any event likely to have affected its stability — high winds, impact from plant or vehicles
- At regular intervals not exceeding 7 days during use
The inspection must be carried out by a competent person and the results recorded in writing. The record must include the date and time of inspection, the location, the type and condition of the scaffold, the name and position of the inspector, and details of any defects found and the action taken.
For mobile tower scaffold, this means a written pre-use inspection before each period of use is a legal requirement where the tower could result in a fall of more than 2 metres.
Download a mobile scaffold risk assessment template — ready in 60 seconds
SafetyPod offers a professionally drafted, HSE and PASMA-compliant mobile scaffold risk assessment template covering all the hazards and controls for mobile tower scaffold erection, use, and dismantling — including pre-use inspection requirements, outrigger deployment, ground condition assessment, weather monitoring, and exclusion zone management.
Fully editable in Word. Adapt it to your specific tower configuration and site, and it's ready to submit.
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Frequently asked questions
Do I need a PASMA qualification to use a mobile tower scaffold?
PASMA training is not a statutory legal requirement in the same way as some other qualifications, but it is the accepted industry standard for demonstrating competence in mobile tower scaffold erection and use. Most principal contractors require evidence of PASMA qualification as a condition of site access. The legal requirement under the Work at Height Regulations 2005 is competence — PASMA training is the recognised way to demonstrate it.
How often does a mobile tower scaffold need to be inspected?
A written inspection must be completed before each period of use where the tower could result in a fall of more than 2 metres, and at intervals not exceeding 7 days during ongoing use. Additionally, it must be inspected following any event likely to have affected its stability — high winds, impact, or any modification.
Can a mobile tower be moved while someone is on it?
No. Moving a mobile tower while anyone is on the platform is one of the most serious working at height violations — it is a direct cause of fatal incidents. All operatives must descend to the ground before the tower is moved. This must be stated explicitly in both the risk assessment and the method statement, and reinforced at the pre-start toolbox talk.
What is the maximum height for a mobile tower scaffold?
The maximum height depends on the base dimensions and whether outriggers are deployed. PASMA guidance specifies height-to-base ratios for both indoor use (3:1) and outdoor use (3:1 with outriggers). As the ratio varies by tower manufacturer and configuration, always follow the manufacturer's instructions and PASMA guidance for the specific tower being used.
Does a scaffold risk assessment cover both erection and use?
Yes — a comprehensive scaffold risk assessment should cover the hazards associated with erection, use, and dismantling as separate phases, since the risk profile differs significantly between them. Erection and dismantling carry the highest risk because protective measures are not fully in place during those phases.
> Related: Scaffold erection and use is a form of work at height. See our complete guide to the working at height risk assessment for the full legal framework.
Summary
Scaffold and mobile tower scaffold work is among the highest-risk activity on UK construction sites. A compliant scaffold risk assessment must identify the specific hazards of erection, use, and dismantling; specify the control measures in place including competency requirements, inspection records, outrigger deployment, and ground condition assessment; and be signed by a competent person before work starts. For mobile tower scaffold, a PASMA-trained operative and a written pre-use inspection record are the minimum standard expected by UK principal contractors and HSE inspectors.
→ Download the Use of Mobile Scaffold Platforms Risk Assessment — £3.99
Written by the SafetyPod team — NEBOSH-qualified H&S professionals with hands-on experience across UK construction, civil engineering, and facilities management. All content is written to current HSE guidance, Work at Height Regulations 2005, and PASMA compliance.
Last reviewed: May 2026