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UK scaffolding regulations: Work at Height, TG20:21, SG4 and CISRS

British scaffolding sits on one statute, a handful of schedules and a set of industry documents that the regulator treats as the benchmark. This guide maps each layer, from the 950 mm guard-rail rule to the CISRS Advanced Scaffolder card and the council licence for a scaffold over the pavement.

By Ole Emil Frikstad Urstad · How the numbers are computed ·

SGB CUPLOK scaffolding around a house of 11.4 × 5.3 m with a gabled roof (eaves 4.5 m, ridge 6 m), drawn by the ScaFix 3D model
ScaFix render of the 11.4 × 5.3 m example house with an SGB Cuplok system scaffold, decks and guard-rails on every lift.

What regulations apply to scaffolding in the UK?

The Work at Height Regulations 2005 are the core law: Schedule 2 sets guard-rails of at least 950 mm with gaps no larger than 470 mm, and Schedule 3 requires calculations unless a standard configuration such as NASC TG20:21 or TG30 is used. CDM 2015 frames the project, CISRS cards prove competence and councils license pavement scaffolds.

How do the UK rules fit together?

Think of the system as four layers, each answering a different question:

LayerDocumentWhat it decides
StatuteWork at Height Regulations 2005 (WAHR)Duties to plan, choose equipment and protect edges, with technical detail in nine schedules
ProjectCDM 2015Who plans the job, who coordinates it, when HSE must be notified
Industry benchmarkNASC TG20:21 (tube and fitting), TG30 (system), SG4:22 (falls during erection)What counts as a standard configuration and a safe erection method
Product standardsBS EN 12811-1, BS EN 39, BS 1139, BS EN 74How components and designs perform

On top of that sit people (CISRS cards), the public highway (a council licence) and paperwork (the compliance sheet or design, and the handover). HSE's scaffolding guidance ties the layers together. How the 950 mm rail and the 7-day inspection compare with other countries is set out in scaffolding regulations by country.

What do the Work at Height Regulations 2005 schedules require?

The regulations themselves are short. Regulation 4 covers organisation and planning, regulation 5 competence, regulation 6 the avoidance of risk, regulation 7 the choice of work equipment and regulation 8 points to the schedules for particular equipment. The schedules are where the numbers live:

ScheduleSubjectWhy a scaffold planner cares
1Existing places of work and access at heightRoofs and floors you step off onto
2Guard-rails, toe-boards, barriersEdge protection dimensions
3Working platforms (Part 2: scaffolding)Calculations, plan, supervision
4Collective safeguards for arresting fallsNets and airbags
5Personal fall protection systemsHarness and lanyard use
6LaddersLadder access to lifts
7Particulars of an inspection reportSee the inspection checklist

Schedule 2: guard-rails and toe-boards

Guard-rails are the main defence against falls from height (what the fall statistics show). For construction work, Schedule 2, paragraph 3 sets three rules. The top guard-rail must be at least 950 mm above the edge a person could fall from (910 mm is tolerated only for protection that was already fixed when the regulations came into force). Toe-boards must be suitable and sufficient to stop people, materials and objects going over. Any gap between an intermediate rail and the next protection must not exceed 470 mm. Paragraph 5 adds that a lateral opening is allowed only at a ladder or stair access point, and a rail removed for a task must go back as soon as practicable, with compensating measures while it is out.

Note what the schedule does not do: it does not prescribe a double guard-rail or brick guards. Those come from TG20:21 configurations or a design. The statute sets the minimum gap and height; the benchmark documents decide the hardware.

Schedule 3 Part 2: the scaffolding rules

Paragraph 7 of Schedule 3 demands strength and stability calculations for scaffolding unless a note of calculations already covers the structure or it is assembled in conformity with a generally recognised standard configuration. Paragraph 8 requires an assembly, use and dismantling plan drawn up by a competent person, which may be a standard plan topped up with the specific details. Paragraph 9 keeps that plan available to everyone concerned until the scaffold is down, and paragraph 12 allows assembly, dismantling or significant alteration only under the supervision of a competent person, by workers with specific training.

Kwikstage scaffolding around a house of 11.4 × 5.3 m with a gabled roof (eaves 4.5 m, ridge 6 m), drawn by the ScaFix 3D model
The same example house planned with a Kwikstage system scaffold, showing the bay layout and edge protection.

Where does CDM 2015 come in?

CDM 2015 does not have a scaffolding chapter, but it frames every job the scaffold serves. A project is notifiable to HSE when the construction work is scheduled to last longer than 30 working days with more than 20 workers on site at the same time, or to exceed 500 person days, regulation 6(1). Schedule 3 lists work involving particular risks, and its first item includes falling from a height where the risk is particularly aggravated by the nature of the work or the environment. That list feeds the construction phase plan, so a tall facade scaffold, a scaffold over a live roof or one beside a railway is something the principal designer and principal contractor must address before the first tube arrives.

In practice CDM is why the scaffold contractor asks for loads, programme, access routes and ground information at tender stage: HSE's guidance lists duration, loading, access, ground conditions and building details as the information the user should give the contractor.

What is TG20:21, and when is a design needed?

TG20 is NASC's technical guidance for tube and fitting scaffolding, built to work with BS EN 12811-1. The 2021 edition is delivered through the NASC ePortal as an Operational Guide, a Design Guide and an eGuide that generates compliance sheets. A compliance sheet is a short record of the configuration (bay length, lift height, ties, boarded lifts, sheeting) that shows the scaffold sits inside the guidance.

The edition matters on older paperwork. When TG20:21 went on sale in April 2021, NASC said that scaffolds already built to TG20:13 remained acceptable and needed no modification, and that TG20:13 was expected to be formally withdrawn that autumn in favour of TG20:21 (Construction Enquirer, 12 April 2021). A new scaffold today is checked against TG20:21.

For system scaffolds (cuplock, ringlock and similar), NASC's TG30 now plays the same role: an Operational Guide, a Design Guide and an eGuide, recently extended with birdcage configurations for cup, wedge and rosette systems. Manufacturers' own guidance remains the other route for system kit.

When does the scaffold need a bespoke design?

The NASC FAQ gives the simplest test: if the eGuide cannot produce a compliance sheet, the scaffold needs a bespoke design with input from a competent engineer. HSE lists typical cases that fall outside standard configurations:

  • shoring scaffolds, and cantilevered or truss-out scaffolds
  • access scaffolds with more than two working lifts in use at once
  • towers that need guys
  • slung or suspended scaffolds, and boiler scaffolds
  • anything modified so that it leaves the standard configuration

HSE also expects the contractor to come back with the design basics: scaffold type, bay length, lift height, load class, leg loads and tie spacing. If you have to compare classes, the load classes guide explains what each one carries.

What does SG4:22 say about preventing falls?

SG4 is NASC's guidance on preventing falls during erection, alteration and dismantling, the moments when the scaffold itself is incomplete. The current edition, SG4:22, is aimed at those who manage scaffolding operations and keeps the Scaffolders' Safe Zone method at its centre. HSE summarises the priority as establishing collective fall protection first, so that scaffolders depend less on personal fall arrest. The CISRS Labourer card rules refer to it too: a labourer may work from a fully boarded platform with a single guard-rail and a harness only after SG4 training and with the employer's approval.

Which British and European standards apply to the components?

  • BS EN 12811-1:2003 sets performance requirements and general design methods for access and working scaffolds. BSI lists it as current; it excludes rope-suspended platforms, mobile access towers, power-operated platforms, roof-work protection scaffolds and temporary roofs.
  • BS EN 39 covers loose steel tubes for tube and coupler scaffolds. Note that BSI's catalogue shows the 2001 edition as withdrawn on 21 May 2026, so ask your supplier which edition their tube is certified to.
  • BS EN 74 covers the steel right-angle, swivel, sleeve and parallel couplers.
  • BS 1139-2.2:2009+A1:2015 picks up what EN 74 leaves out, such as aluminium couplers, putlog couplers, toe-board clips and castors. BSI shows it as current but under review.

What are the CISRS cards and how do you progress?

The Construction Industry Scaffolders Record Scheme is the industry's competence card scheme; HSE says each scaffold gang needs at least one competent scaffolder trained for the type of scaffold, and complex structures usually need an Advanced Scaffolder. All cards are issued by NOCN and need a CITB Health, Safety and Environment test passed within the last two years or an accepted exemption (CISRS FAQ).

CardWhat the holder may doTraining requiredValidity / renewal
LabourerSupport work from a safe position; may not erect, alter or dismantleCOTS course5 years
Trainee ScaffolderScaffolding only under direct supervision of a qualified scaffolderLabourer card held 3 months, then Part 1 and Part 2Two 18-month cards
ScaffolderLead a gang on basic scaffolds as defined in TG20COTS, Part 1, Part 2, NVQ Level 2, 1-day skills test5 years
Advanced ScaffolderLead a gang in all operations, including complex designed structuresScaffolder card 12 months, Advanced course, NVQ Level 3, 2-day skills testRenewal: 2-day refresher/CPD course

Renewal for Scaffolder and Advanced cards is a two-day refresher or CPD course; Labourers repeat COTS. System scaffold endorsements come through the separate System Scaffold Product Training Scheme. When you check a card on site, check the grade against the structure: a Scaffolder card covers basic scaffolds as defined in TG20, not a cantilevered loading bay that needs a design.

When do you need a scaffold licence from the council?

Any scaffold that obstructs a highway, footway included, needs a written licence from the highway authority under section 169 of the Highways Act 1980. The authority must issue it if you give the particulars it reasonably asks for, and may refuse only if the scaffold would cause unreasonable obstruction or a less obstructive structure would do. Once licensed, you must light the scaffold from half an hour after sunset to half an hour before sunrise, follow the authority's directions on traffic signs and accommodate statutory undertakers' apparatus. Working without a licence is an offence with a fine up to level 5 on the standard scale. HSE adds a practical point: avoid erecting or striking over busy pavements, and consider a footpath or road closure.

What should the handover certificate contain?

There is no statutory handover certificate, but NASC recommends that every scaffold is handed over with one and that clients ask for it at tender. Its FAQ suggests including tie test records, the compliance sheet or design, the first inspection details and signatures from both sides. NASC's SG35:21 covers the handover itself and the first statutory inspection that follows it. The certificate is the moment the scaffold passes from the erector to the user. From then on the user's employer must make sure the statutory inspections under regulation 12 happen, often by contracting the scaffolder to do them.

How ScaFix fits in

ScaFix lets you brief the scaffold contractor with bay lengths, lifts and edges on many systems before the TG20:21 or TG30 compliance sheet is drawn up; it does not issue that sheet, as the methodology page explains.

Planning information only, not a compliance sheet or a design. HSE expects a TG20:21 or TG30 compliance sheet or a bespoke design under Schedule 3 of the Work at Height Regulations 2005, built to the manufacturer's instructions, and under regulation 12 a competent person inspects the scaffold before first use, at least every 7 days and after high winds or alterations.

Frequently asked questions

What is the minimum guard-rail height on a UK scaffold?

At least 950 mm above the edge for construction work, under Work at Height Regulations 2005 Schedule 2. Gaps between rails and other protection may not exceed 470 mm.

Is TG20 a legal requirement?

No document named TG20 appears in the regulations, but Schedule 3 accepts a recognised standard configuration instead of calculations, and HSE and NASC treat TG20:21 (and TG30 for system scaffolds) as that configuration. Outside it, you need a design. TG20:21 is the 2021 edition, with an eGuide that issues compliance sheets; it replaced TG20:13.

How high must a toe board be in the UK?

The Work at Height Regulations set no figure: Schedule 2 only says toe-boards must be suitable and sufficient to stop people, materials and objects falling. The height comes from the TG20:21 or TG30 configuration or the system manufacturer's instructions, so check it there.

How often must scaffolding be inspected in the UK?

A working platform from which someone could fall 2 m or more may not be used unless it was inspected in that position within the previous 7 days (regulation 12(4)), and again after anything that could affect its safety.

Which CISRS card do I need to erect scaffolding?

A Scaffolder card to lead a gang on basic structures, an Advanced Scaffolder card for complex designed structures. Trainees may only work under direct supervision, and Labourers may not erect, alter or dismantle.

Do I need a licence to put scaffolding on the pavement?

Yes. Section 169 of the Highways Act 1980 requires a written licence from the highway authority, usually the council, for any scaffold that obstructs the highway or footway.

Sources

Primary sources used for this article, with the date each was read.