Failure of cast iron beams
Many buildings utilising cast iron (CI) continue to give good service with adequate reliability when used in a risk assessed manner and current best practice documents. As is normal with this type of beam, there is rarely any apparent warning of imminent collapse.
Certain combinations of actions may lead to an unsafe situation that should be investigated by a competent structural engineer. These situations include:
- Additional loading on a CI beam, typically arising from further deadweight added since original completion. The unregulated increase of load on a structure should always be a matter of concern.
- Long-standing ingress of water leading to corrosion, deterioration of the concrete infill, and loss of any composite action. Extended basements or roof garden arrangements are particularly prone to this action.
- The beams working at high levels of stress as originally installed. This is more likely in a domestic structure where the beam may have been sized by rule of thumb.
Professionals working in this field, or with clients responsible for property of this type and era, should be aware of these issues and be ready to advise the relevant parties of the need for a structural risk assessment if the identified conditions exist.
[edit] Related articles on Designing Buildings Wiki
- Brittle fracture.
- Cast iron.
- Conservation of Architectural Ironwork.
- Defects in construction.
- Degradation of construction materials.
- Failure of metals.
- Flat roof defects.
- Girder.
- Graphitisation.
- Iron.
- Metal.
- Roofing defects.
- Rust.
- Structural failures.
- Structural steelwork.
- Tension.
- Weathering steel.
Featured articles and news
Costs and insolvencies mount for SMEs, despite growth
Construction sector under insolvency and wage bill pressure in part linked to National Insurance, says report.
The place for vitrified clay pipes in modern infrastructure
Why vitrified clay pipes are reclaiming their role in built projects.
Research by construction PR consultancy LMC published.
Roles and responsibilities of domestic clients
ACA Safety in Construction guide for domestic clients.
Fire door compliance in UK commercial buildings
Architect and manufacturer gives their low down.
Plumbing and heating for sustainability in new properties
Technical Engineer runs through changes in regulations, innovations in materials, and product systems.
Awareness of the Carbon Border Adjustment Mechanism
What CBAM is and what to do about it.
The new towns and strategic environmental assessments
12 locations of the New Towns Taskforce reduced to 7 within the new towns draft programme and open consultation.
Buildings that changed the future of architecture. Book review.
The Sustainability Pathfinder© Handbook
Built environment agency launches free Pathfinder© tool to help businesses progress sustainability strategies.
Government outcome to the late payment consultation, ECA reacts.
IHBC 2025 Gus Astley Student Award winners
Work on the role of hewing in UK historic conservation a win for Jack Parker of Oxford Brookes University.
Future Homes Building Standards and plug-in solar
Parts F and L amendments, the availability of solar panels and industry responses.
How later living housing can help solve the housing crisis
Unlocking homes, unlocking lives.
Preparing safety case reports for HRBs under the BSA
A new practical guide to preparing structural inputs for safety cases and safety case reports published by IStructE.
Male construction workers and prostate cancer
CIOB and Prostate Cancer UK encourage awareness of prostate cancer risks, and what to do about it.





















