Scaffolding guides

Scaffold regulations: UK and US

The UK rules are in the Work at Height Regulations 2005, with the NASC TG20 guidance for tube-and-fitting scaffolds; the US rules are OSHA 29 CFR 1926 Subpart L. Here are the main requirements with their section numbers.

By Ole Emil Frikstad Urstad · How the numbers are computed · Last updated 23 October 2026

Layher Blitz around the example house, as ScaFix draws it in 3D.

What are the main scaffold regulations?

In the UK, scaffolds are erected, altered and dismantled only under the supervision of a competent person by trained people, inspected after assembly and every 7 days where there is a fall of 2 m or more, with a top guard-rail of at least 950 mm and no gap over 470 mm. In the US, a competent person supervises erection and inspects before each shift; fall protection is needed above 10 ft (3.1 m); toprails are 38–45 in; and a scaffold taller than four times its base width must be tied.

Try one week – €9.90 See the demo house in 3D See ScaFix

€9.90 for 7 days. Does not renew.

United Kingdom

United Kingdom
Topic	Requirement	Source
Competence	Nobody plans, supervises or does work at height unless competent, or trained under a competent person's supervision	WAHR 2005 reg. 5
Erection	Assembly, dismantling or significant alteration only under a competent person's supervision, by people with specific training	WAHR 2005 Sch. 3 Part 2
Design	Strength and stability calculations unless a note of calculations exists or the scaffold is a generally recognised standard configuration; TG20 compliance sheets serve as that for tube and fitting	WAHR 2005 Sch. 3 Part 2; NASC TG20:21
Inspection	After assembly, at suitable intervals and after exceptional events; platforms with a 2 m+ fall inspected within the previous 7 days; written report within 24 hours	WAHR 2005 reg. 12, Sch. 7
Guard-rails	Top guard-rail at least 950 mm; gap between intermediate rail and other protection at most 470 mm; suitable toe-boards	WAHR 2005 Sch. 2
Mobile towers	Erected by trained people (advance guard rail or 3T method); inspected after assembly and every 7 days in construction; reduce to max 4 m to move	HSE tower scaffolds

United States (OSHA)

United States (OSHA)
Topic	Requirement	Source
Capacity and design	Each scaffold supports its own weight and at least 4 times the intended load; designed by a qualified person; frame and tube scaffolds over 125 ft by a registered engineer	29 CFR 1926.451(a), 1926.452
Ties	Height over 4:1 of the base: restrained at the 4:1 height, then every 20 ft (≤ 3 ft wide) or 26 ft vertically, at each end and every 30 ft horizontally	29 CFR 1926.451(c)(1)
Supervision and inspection	Erected, moved or dismantled under a competent person; inspected before each shift and after any event that could affect it	29 CFR 1926.451(f), (g)
Fall protection	Required above 10 ft (3.1 m); toprail 38–45 in on scaffolds placed in service after 1 Jan 2000, midrail midway; toeboards at least 3½ in where objects could fall	29 CFR 1926.451(g), (h)
Training	Users trained by a qualified person; erectors and inspectors trained by a competent person; retraining when needed	29 CFR 1926.454
Mobile scaffolds	Braced, casters locked when stationary; riding only on surfaces within 3° of level and at 2:1 or less while moving, among other conditions	29 CFR 1926.452(w)

Waco Frame 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 — Waco Frame around the example house, as ScaFix draws it in 3D.

What ScaFix does – and doesn't

ScaFix plans the scaffold with each system's own bay lengths and rules (US systems with OSHA tie spacing) and lists every part, guardrails, toe boards, braces and ties included.
ScaFix is a planning tool, not a structural design: the manufacturer's instructions, a competent person and the inspections above always apply.

Sources

legislation.gov.uk, eCFR and HSE, read on 23 October 2026; TG20:21 from trade press (NASC's own page could not be opened).

Questions and answers

How often must a scaffold be inspected in the UK?

After assembly, after exceptional events and, for construction platforms with a fall of 2 m or more, within the previous 7 days (Work at Height Regulations 2005 reg. 12).

When does OSHA require a scaffold to be tied?

When its height is more than four times its least base dimension: ties at that height, then every 20 ft or 26 ft vertically and every 30 ft horizontally (29 CFR 1926.451(c)(1)).

Does ScaFix produce a TG20 compliance sheet or a structural design?

No. ScaFix is a planning tool with a parts list; designs and compliance sheets come from the scaffold designer.

Try one week – €9.90 See the demo house in 3D See ScaFix

€9.90 for 7 days. Does not renew.