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CROSS Newsletter -- No.13
Two Building Collapses

The building was a two storey corner (end of terrace) property fronting a very busy, narrow major route in an area which is normally busy with pedestrians and traffic. On the ground floor there was a shop and there was residential accommodation above. Work had been in progress, without Planning or Building Regulations approval, for about a month to create a basement and loft conversion. A Building Control Surveyor visited the property and advised the builder to stop work until the permissions had been resolved. However, work continued.
Internal cross walls had been removed and chimney breasts had been removed from the party wall. It appeared that the internal area was gutted and the floors were supported on new steel beams spanning parallel to the front from party wall to flank wall. The robustness of the structure had been seriously compromised as there was virtually no lateral stability system. The external walls had been underpinned, rather poorly, onto largely noncohesive soil, and at the time of failure a mini digger was excavating for the basement. It is suspected that the digger undermined the toe of the underpinning.
As a consequence the underpinning began to kick inwards and the pavement adjacent to the flank wall started to collapse. Police and Fire Brigade services were summoned and immediately called in Building Control. The building control engineer who was summoned to the scene was concerned about stability, but was unable to establish the extent of the work without entering the building. He decided that it was not safe to do so. Within minutes the building collapsed into the basement and scaffolding was thrown across the streets. There were no injuries.

CROSS comments:
The lesson to be learned is that this alteration work showed a total lack of understanding of the first principles of building stability and of the way that stability can be compromised by alterations and inadequate phasing of the work. Planning Permission and Building Regulations approval are an essential pre-requisite to carrying out alterations. The involvement of a structural engineer or building surveyor would have prevented this needless destruction. The skill and ability of the building control engineer called to the scene is to be admired. (Report 123)

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DOMESTIC COLLAPSE NO. 2

This is a case of collapse caused by a builder carrying out underpinning  works. The property is a semi detached house which at sometime had been part of a larger terrace. It had only recently been bought by a first time buyer who noticed a problem with the gable wall and a structural engineer was commissioned to investigate. The recommendation was that a new external leaf should be constructed off a new foundation including underpinning of the existing wall in short sections. The report also described works to be carried out before underpinning and these included a requirement to tie the existing wall into the main house. The engineer gave advice to the owner on selection of a suitably qualified contractor and also offered to supervise.
Unfortunately the owner decided to engage a builder on the recommendation of a friend.
The builder ignored the engineer’s report in respect of

preliminary works and sequencing of excavations. Instead a trench was excavated the full length of the gable and left overnight without any temporary support. During the early hours the wall collapsed and the photo shows the condition of the wall when the Building Control Officer attended. The occupiers, including a baby asleep in the cot in the rear
bedroom, were lucky not to be injured and were rescued by the Fire Service.
To make matters worse the builder is uninsured and the owner’s insurers will not accept liability.

CROSS comments:
This is a tragedy for the owner who unwittingly appointed an incompetent builder after starting on the correct path by engaging a structural engineer. All alteration work should be carried out by competent builders who carry appropriate insurance - but how is an owner to know this? Cowboy builders are the stuff of TV exposures but more needs to be done to inform the public of the risks involved in appointing the wrong person or firm. There is no regulation or licensing system in the industry which covers this gap and CROSS would be pleased to have views on the subject. These collapses are similar to some of the cases the HSE Specialist Inspectors of Construction Engineering have investigated, which involved fatalities, such as at Stanley Road, Bootle (29 January 2000) in which a man died. (Report 128)

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