1. Introduction
Temporary works anchors are routinely treated as lower-risk, short-term fixings. In London construction, that assumption is increasingly unsafe. Under the Building Safety Act and Building Safety Regulator (BSR) regime, the distinction between temporary and permanent is no longer determined by intent alone, but by consequence, load path and evidential traceability.
BS 8539 provides the technical framework for post-installed anchors regardless of programme duration. Where temporary works anchors influence stability, load transfer, restraint or safety-critical sequencing, BS 8539 expectations and building safety duties apply in full. This article explains when that threshold is crossed, how responsibility shifts, and why misclassification of temporary anchors is now a recurrent compliance failure.
2. Why temporary works anchors are no longer a low-risk category
Temporary works anchors are often installed quickly, late in the programme and under commercial pressure. They are frequently removed, altered or forgotten once their immediate purpose has passed. Historically, this has encouraged a belief that temporary anchors sit outside formal design and verification regimes.
That belief no longer holds.
In dense London sites, temporary works anchors commonly restrain façades, retain partial structures, support propping systems, stabilise demolition sequences or control construction-stage load paths. Failure of these anchors can result in disproportionate harm, even if the anchor was never intended to remain in the finished building.
BS 8539 does not distinguish between temporary and permanent anchors by programme duration. It distinguishes them by function, load path and consequence of failure. Where anchor failure would create a safety risk, BS 8539 applies regardless of whether the anchor is labelled temporary.
3. How BS 8539 applies to temporary works anchors
BS 8539 is a code of practice governing the selection, installation, inspection and testing of post-installed anchors. It applies wherever anchors are relied upon to perform a defined function in concrete or masonry.
For temporary works anchors, this means BS 8539 applies when anchors:
- resist load rather than provide positional convenience
- contribute to stability, restraint or structural integrity
- interact with permanent works or adjacent assets
- are relied upon for a defined period rather than momentary use
The standard does not allow anchors to fall outside control simply because they are planned for removal. If the anchor’s performance matters, its compliance matters.
Temporary intent does not negate BS 8539 applicability. The trigger is reliance. If the works rely on the anchor behaving as assumed, BS 8539 expectations apply.
4. Temporary works vs permanent works: where classification fails
The most common compliance failures occur at the boundary between temporary and permanent works. Examples include:
- anchors initially installed for temporary restraint but later retained
- anchors supporting temporary loads that exceed permanent design actions
- anchors installed under temporary works procedures but relied upon during permanent works sequencing
- anchors left in situ and forgotten without formal acceptance
In these scenarios, the anchor’s legal and technical status changes, often without anyone explicitly acknowledging it.
Anchor classification is not fixed at installation. It evolves with use. When use changes, responsibility and compliance requirements change with it.
Failure to recognise this transition is one of the most common causes of undocumented safety-critical anchors on UK sites.
5. Design responsibility for temporary works anchors
Temporary works anchors are not exempt from design responsibility. Where an anchor resists load, someone must define what load it resists, on what basis and with what margin.
Responsibility typically sits as follows:
- Designers define performance where anchors interact with permanent works or structural stability.
- Temporary Works Coordinators control sequencing and interface risk.
- Contractors or specialist installers assume design responsibility when selecting anchor systems without prescriptive design input.
- Manufacturers provide product data, not project-specific design approval.
Testing does not replace design responsibility.
Selecting a temporary works anchor is a design act when performance is relied upon. Under BS 8539, selection without defined assumptions creates unowned risk.
6. Installation and competence: why temporary does not reduce standards
BS 8539 requires that anchors are installed by competent operatives, following defined procedures, within known assumptions. This applies equally to temporary works anchors.
Common temporary works installation risks include:
- unverified substrate conditions
- reduced embedment to avoid reinforcement
- inconsistent hole cleaning
- torque or setting force not controlled
- substitute products used due to availability
These are often tolerated because the anchor is temporary. Under BS 8539, they invalidate compliance.
Temporary duration does not justify reduced installation control. BS 8539 treats installation quality as a condition of performance, not a convenience.
7. Testing temporary works anchors: what testing does and does not prove
Testing is frequently used to legitimise temporary works anchors. This is a misunderstanding of BS 8539.
Testing can confirm that an anchor behaves as expected at the time of testing, in that substrate, under that load. It does not:
- approve the design
- override manufacturer limitations
- compensate for unknown assumptions
- guarantee future performance
Suitability testing may be appropriate where substrate conditions are uncertain. Acceptance testing may support quality control. Neither transfers design responsibility.
Testing verifies assumptions. It does not create them. Where assumptions are undefined, testing creates false confidence rather than compliance.
8. Evidence and records: temporary anchors still need a paper trail
Under modern compliance regimes, undocumented anchors are treated as uncontrolled risk. For temporary works anchors, defensible evidence should include:
- purpose and function of the anchor
- design assumptions or selection rationale
- installation records and competence evidence
- testing records (where applicable) and interpretation
- confirmation of removal or formal acceptance into permanent works
Anchors that are removed should be recorded as such. Anchors that remain must be accepted formally. An anchor that cannot be traced cannot be defended. Temporary status does not remove the need for evidence.
9. Temporary works anchors in the Building Safety Regime
Under the Building Safety Act, dutyholders must demonstrate control of safety-critical risks throughout the building lifecycle. Temporary works anchors increasingly fall within that scope where their failure could reasonably affect building safety.
In Gateway reviews and post-completion scrutiny, the question is not whether an anchor was intended to be temporary, but whether its risk was managed competently.
BS 8539 becomes enforceable in practice where anchor failure would have building safety consequences. Temporary works anchors are not exempt from that logic.
10. Conclusion
Temporary works anchors sit at one of the most misunderstood interfaces in UK construction. BS 8539 makes clear that reliance, not intent, determines responsibility. Where temporary works anchors resist load, affect stability or interact with permanent works, BS 8539 and building safety duties apply.
Misclassifying anchors as temporary does not reduce risk. It conceals it. In London’s regulated construction environment, that concealment is no longer tolerated.
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Expert Verification & Authorship: Mihai Chelmus
Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
