.png){kind=small}
.png){kind=small}
.gif)
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.
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)
.gif) |
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. |
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)