Skip to main content

CROSS Safety Report

Engineer asked to provide calculations for a dangerous refurbishment

Report ID: 1295 Published: 21 May 2024 Region: CROSS-UK


Overview

This is about the refurbishment of a historic, traditional build house and the difficulties encountered by a reporter when interacting with the owner over the construction of a new basement adjacent to the existing east wing. There had been a partial collapse and there was an excavation adjacent to the wall. 

Key Learning Outcomes

For clients:

  • Seek advice from suitably qualified and experienced designers or inspectors, and accept their professional advice

For designers and inspectors:

  • Provide advice in a professional manner and confirm all such advice in writing setting out actions required and the consequences of not acting as advised

Full Report

Find out more about the Full Report

Our secure and confidential safety reporting system gives professionals the opportunity to share their experiences to help others. If you would like to know more, please visit the reporting to CROSS-US page.

This is about the refurbishment of a historic, traditional build house and the difficulties encountered by an engineer, the reporter, when interacting with the owner over the construction of a new basement.

The reporter’s firm were asked by the architect to attend the site and were sent a topographical and measured building survey which showed a partial collapse and an excavation adjacent to the wall. The reporter understands that building control requested that an engineer appraise the situation.

The gable of the east wing had partly collapsed. The remaining wall featured many large cracks

The property had been extended several times in the past and was now being renovated by the owner. The eastern wing comprises two floors with a purlin roof plus a brickwork basement featuring a vaulted ceiling.

The gable of the east wing had partly collapsed. The remaining wall featured many large cracks (in some cases several centimetres wide) and there was clear evidence of vertical movement. There was a large excavation adjacent to the wall some four metres deep and it appeared that the instability had been instigated by the formation of this excavation.

A large and complex scaffold arrangement had been erected against the structure in an effort to provide some lateral stability. There were some obvious inherent problems including:

  • Long slender scaffold tubes in compression but not braced against buckling failure
  • No anchorage or kentledge to resist overturning
  • No cross bracing in some places

There was a new blockwork wall at ground floor level perpendicular to the gable some two and a half metres high and directly adjacent to the unsupported excavation but which didn’t appear to be offering any meaningful structural benefit. 

The neighbouring house was adjacent to the excavation. The scaffold and new wall failed to address several other potential failure modes, specifically:

  • Vertical translation of the wall by a combined bearing capacity / stability failure
  • Outward thrusting of the basement arch barrel
  • Collapse of the unsupported excavation (including a collapse of the adopted public highway)
  • Collapse of the footings to the neighbouring house

Despite these points, the client told the reporter, "it’s safe now" and asked the reporter’s firm for ‘calculations’ rather than a solution.

The reporter advised the client that they must not go near the structure and that the highway must be cordoned off

Upon checking the actual measurements taken against the original survey, it appeared that that the excavation had been over deepened following the collapse. Most concerning of all, the client was still using the house as a residence with their children having access to some parts of the eastern wing and with none of the external areas cordoned off.

The reporter advised the client that they must not go near the structure and that the highway must be cordoned off as, with higher wind and rain during the winter, the annex was at risk of complete collapse. They also advised that, following restriction of access to cope with the short-term risk, the client should seek planning permission to demolish the wing as the reporter considered it to be both too dangerous to work around and beyond practical repair.

The reporter remains very worried about the safety of this structure and is frustrated that they cannot effect more change

The reporter contacted building control via the local dangerous structures phone number to discuss the matter and were asked to leave a message. More than a month later, they had not received a response but eventually the matter was escalated within the relevant department. The Health and Safety Executive (HSE) website was used to report a dangerous situation and there was a reply stating they would not take action as the issue fell under the remit of building control. 

The reporter also made contact with Highways (although there does not seem to be a formal mechanism for this) and wrote an email to them outlining their concerns. No response was received.

The reporter remains very worried about the safety of this structure and is frustrated that they cannot effect more change. The request for ‘calculations’ by the client and the statement they made claiming that the structure was safe implies that they wanted a structural engineer to undertake a tick box exercise (probably because building control insisted on this) rather than because they felt an engineer could add value to the project. There appeared to be a palpable absence of any concern regarding what was clearly a very dangerous structural condition.

The reporter believes they have learnt the following lessons:

  1. From this experience, and others, it appears that some clients and members of the public have contempt for the importance of designers and consultants. There seems to be a resistance to designers and consultants ‘over-intellectualising’ construction in some way. This can put clients (and indeed the public) at risk without them realising it. It is the reporter’s view that the industry must try to make people realise how important our function is, not to make money, but for the sake of public safety.
  2. The importance of identifying and addressing all forces in a structure remains important. In this instance, the client had partly addressed the lateral stability of the wall (even if it was not satisfactorily resisted) but had not addressed the vertical support to the foundation, the internal forces within the scaffold, the lateral earth pressure, the arch thrusting from the masonry vaulted ceiling, and the adjacent foundation.
  3. The reporter considers building control and other regulatory bodies appear to be dysfunctional. The reporter was very disappointed that they received no response from building control regarding a serious issue until pressed. Historically, the reporter has had good dealings with building control and a discussion between peers has yielded positive outcomes. However, in the view of the reporter, this relationship between consulting engineer and building control appears to be breaking down.

Expert Panel Comments

Find out more about the Expert Panel

An Expert Panel comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-US Expert Panel page.

This tale of woe will be familiar to many of our readers. A lay client that is reluctant to accept good advice on the grounds that they know better, and underfunded local authorities unable to respond to reasonable concerns expressed by professionals.

The report appears a perfect storm combining the “what do experts know” attitude that has been articulated by several high-profile individuals in recent years when faced with forecasts they do not like and an underinvestment in public services.

It is incumbent upon us as suitably qualified and experienced persons to always offer the best advice to our clients. Unfortunately, they are not required to accept this advice. Furthermore, it now seems that any enforcement agencies that did exist are no longer functioning as they once did. All one can do in such circumstances is confirm advice in writing, setting out actions required and the consequences of not acting as advised.

Submit a report

Your report will make a difference. It will help to create positive change and improve safety.

Our secure and confidential safety reporting system gives professionals the opportunity to share their experiences to help others.