Temporary works are the unsung heroes of construction safety. Every building you see rising above London's skyline relies on temporary support systems during construction—props holding up floors while columns are replaced, shoring preventing excavation collapse, scaffolds providing safe access, and formwork shaping concrete until it cures. When temporary works fail, the consequences are catastrophic. Collapses kill workers, damage neighbouring properties, and can destroy months of progress in seconds. At Thane Construction, temporary works safety is not an afterthought; it is engineered, inspected, and managed with the same rigour as permanent structures. This guide explains the temporary works systems we use across London and the safety standards that protect our teams and the public.
What Are Temporary Works?
Temporary works are defined in BS 5975:2019 as "parts of the works that allow or enable construction of, protect, support or provide access to, the permanent works and which might or might not remain in place at the completion of the works." This broad definition covers an enormous range of systems and activities on every construction site.
Common temporary works on London construction sites include:
- Propping systems supporting floors, beams, and structures during alteration or demolition
- Shoring and earth retention preventing excavation collapse in London's variable ground conditions
- Falsework supporting formwork for concrete pours until the concrete achieves sufficient strength
- Formwork moulds into which concrete is poured and from which it is stripped after curing
- Scaffolding and access platforms providing safe working at height
- Temporary bridges and platforms maintaining access over excavations or construction zones
- Facade retention supporting existing building fronts during internal redevelopment
- Underpinning support maintaining stability while foundations are strengthened or extended
The Health and Safety Executive reports that temporary works failures account for a significant proportion of construction-related incidents. Proper design, competent execution, and rigorous inspection are non-negotiable.
BS 5975:2019 — The Temporary Works Standard
BS 5975:2019 is the British Standard for temporary works procedures and the permissible stress design of falsework. It provides the framework for managing temporary works risk on UK construction sites, including London. The standard mandates a systematic approach to temporary works design, erection, use, and dismantling.
The Temporary Works Coordinator (TWC)
Every construction project involving temporary works must appoint a Temporary Works Coordinator (TWC). The TWC is responsible for coordinating all temporary works activities, ensuring designs are prepared by competent persons, checking designs before work begins, and maintaining the temporary works register. At Thane Construction, our TWCs hold relevant qualifications and have extensive experience managing complex temporary works on London's constrained urban sites.
The Temporary Works Supervisor (TWS)
The Temporary Works Supervisor (TWS) assists the TWC, supervising the erection, use, and dismantling of temporary works on site. The TWS ensures that temporary works are built according to the approved design, that inspections are carried out at required intervals, and that any defects or modifications are reported immediately.
Design Checks and Categories
BS 5975 categorises temporary works designs by complexity and risk. Category 0 covers standard proprietary systems used within manufacturer guidelines. Category 1 involves simple bespoke designs checked by the designer. Category 2 requires independent checking by a competent person not involved in the original design. Category 3 demands independent design checking by a chartered engineer for complex or high-risk temporary works.
On London sites, where proximity to neighbouring buildings, public highways, and underground infrastructure creates elevated risk, many temporary works fall into Category 2 or 3, requiring independent verification before erection.
Propping Systems for Structural Support
Propping systems support existing structures during alteration, renovation, or demolition. In London's dense urban environment, where buildings are often attached or closely spaced, propping is essential for safe structural modification.
Acrow Props and Adjustable Props
Acrow props are the most common temporary support in UK construction. These adjustable steel props support loads from 7kN to 170kN depending on size and extension. For typical domestic propping during load-bearing wall removal or beam installation, Acrow props provide cost-effective, rapid deployment support. However, they must never be used at maximum extension under maximum load, and proper sole plates and head plates are essential to prevent punching failure.
Heavy-Duty Propping Towers
For heavier loads, propping towers using system scaffolding components or proprietary systems like PERI, Doka, or RMD Kwikform provide greater capacity and stability. These systems can support hundreds of tonnes and are used for commercial floor propping, bridge support, and facade retention. In London, where Victorian buildings often require significant structural alteration, heavy-duty propping towers are standard equipment on our renovation projects.
Needling and Dead Shoring
Needling involves inserting steel needles through walls to transfer loads to temporary supports while openings are created below. Dead shoring supports vertical loads from above during foundation work or lower-floor alterations. These traditional techniques remain essential for heritage building work in London's conservation areas, where modern propping systems may be impractical or visually intrusive.
Shoring and Excavation Support
London's construction boom has created enormous demand for basement construction, utility installation, and foundation work, all requiring excavation. Shoring prevents excavation collapse, protecting workers and preventing ground movement that could damage adjacent buildings or infrastructure.
Sheet Piling
Sheet piles are driven or vibrated into the ground to create continuous retaining walls around excavations. Steel sheet piles are most common, though vinyl and composite sheets are increasingly used for temporary applications. In London's clay soils, sheet piling provides effective cut-off for groundwater and creates rigid excavation support. For deep basements in Kensington, Chelsea, and Notting Hill, sheet pile cofferdams are standard practice.
Soldier Piles and Lagging
Soldier piles (steel H-sections or tubular piles) installed at intervals with timber or concrete lagging between them provide flexible excavation support. This system is ideal where underground obstructions prevent continuous sheet piling. Soldier piles can be installed by drilling or driving, and the lagging is placed as excavation proceeds in stages.
Trench Boxes and Shields
For utility trenches and narrow excavations, trench boxes and trench shields provide worker protection without full shoring. These proprietary systems are placed in the trench as excavation proceeds and moved forward as work advances. They are essential for safe drainage, sewer, and cable installation work across London.
Ground Anchors and Soil Nailing
For deep excavations where internal bracing would obstruct construction, ground anchors or soil nails provide lateral support from outside the excavation. These systems require specialist design and installation but create completely unobstructed working space inside the excavation. Ground anchors are common for deep commercial basement construction in Central London.
Scaffold Design and Safety
Scaffolding is the most visible temporary work on any construction site. Proper scaffold design and erection are governed by BS EN 12811, TG20:21 guidance, and the Work at Height Regulations 2005. In London, where scaffolds often occupy public highways and footpaths, additional considerations include pavement licences, traffic management, and public protection.
Independent Scaffolds
Independent scaffolds stand clear of the building, supported by standards, ledgers, and transoms. They are the most common type for general construction access. For London's typical 2-4 storey residential projects, independent scaffolds provide safe, versatile access for trades.
Birdcage Scaffolds
Birdcage scaffolds are fully enclosed independent scaffolds used for internal work at height, such as atrium construction, ceiling work, or high-level maintenance. They provide access from all sides and are essential for complex interior projects.
Cantilever and Hanging Scaffolds
Where ground support is impossible—over pavements, railways, or adjacent properties—cantilever scaffolds project from the building facade, or hanging scaffolds are suspended from roof structures. These systems require specialist design and are common on London's constrained commercial renovation projects.
Scaffold Inspection Requirements
All scaffolds must be inspected by a competent person before first use, after any modification, after events that could affect stability (high winds, vehicle impact), and at least every 7 days. Inspection reports must be maintained on site. At Thane Construction, our scaffolds are inspected weekly without fail, with reports uploaded to our digital safety management system.
Falsework and Formwork Systems
Falsework supports formwork during concrete casting. Formwork is the mould into which concrete is poured. Together, these systems shape every concrete structure ever built. Their safe design and erection are critical, as formwork failures during concrete pours are among the most dangerous incidents in construction.
Proprietary Formwork Systems
Modern formwork uses proprietary systems from manufacturers like PERI, Doka, Meva, and RMD Kwikform. These systems include panels, beams, props, and accessories designed to work together with verified load capacities. For London's high-rise and complex concrete projects, these systems provide speed, safety, and quality.
Traditional Timber Formwork
For smaller projects, complex shapes, or one-off elements, traditional timber formwork remains practical. However, timber formwork requires skilled carpenters, thorough design, and careful inspection. The variability of timber strength means safety factors must be generous, and formwork must be inspected before every pour.
Striking Times and Concrete Strength
Formwork must not be struck until concrete has achieved sufficient strength to support its self-weight and construction loads. Striking too early causes collapse or permanent deformation. Striking times depend on concrete mix, ambient temperature, and structural element type. In cold London winters, striking may be delayed by days compared to summer pours. Our engineers verify concrete cube test results before authorising formwork striking.
Facade Retention in London
London's planning policies often require retention of historic facades during redevelopment, particularly in conservation areas and for listed buildings. Facade retention involves supporting the existing building front while the structure behind is demolished and rebuilt. This is among the most complex and risky temporary works in construction.
Facade retention systems typically involve:
- Needle beams inserted through the facade to transfer loads to external supports
- Raking shores providing angled support from the ground to the facade
- Flying shores spanning between retained facades where ground support is impossible
- External steel frames completely supporting the facade independent of the new structure
Facade retention requires Category 3 temporary works design with independent structural engineer checking. Monitoring systems track facade movement throughout demolition and reconstruction, with trigger levels defining when work must stop for investigation.
Inspection, Monitoring, and Record Keeping
Temporary works are not "fit and forget." They require ongoing inspection, monitoring, and maintenance throughout their service life. BS 5975 mandates specific inspection regimes, and Thane Construction exceeds these requirements on every project.
Our temporary works inspection protocol includes:
- Pre-erection checks verifying materials, components, and design compliance
- Post-erection inspections before loading or use
- Weekly inspections during service life, documented with photographs
- Post-event inspections after high winds, heavy rain, vehicle impact, or vibration
- Monitoring systems for high-risk temporary works, with automatic alerts for excessive movement
- Dismantling inspections ensuring safe removal without damage to permanent works
Conclusion
Temporary works are the invisible infrastructure that makes construction possible. From the props supporting your neighbour's ceiling during their extension to the massive shoring systems enabling London's newest skyscrapers, temporary works safety underpins every successful project. The consequences of failure—injury, death, property damage, and project collapse—make temporary works management one of the most critical responsibilities in construction.
At Thane Construction, temporary works are designed by competent engineers, erected by trained operatives, inspected by qualified supervisors, and managed by experienced Temporary Works Coordinators. Our commitment to temporary works safety protects our workforce, the public, neighbouring properties, and our clients' investments on every London project we undertake.
For temporary works design, installation, or safety advice on your London construction project, contact Thane Construction. Call 07383 691639 or visit our contact page to speak with our engineering team.