Some 20 years or so back news cameras caught the moment a scaffold collapsed in Knightsbridge, central London. Not an uncommon occurrence, but one not commonly ‘caught’ on T.V., so, as no-one had been injured, what could have been a tragedy made for some very entertaining viewing on the evening news. It had all started in the later afternoon as workers reported that the scaffold, erected along the pavement in front of a four-storey brick terrace, had become unstable.
The project involved a terrace façade which was being retained as a frontage to what would become an entirely new office development; all that of course a whim of the planners who wanted to retain the street’s character. Thus it was that the early 19th century building, comprising 9” party walls, timber floor joists, and a mix of brick and stud internal partitioning, was stripped out to make way for a steel frame and concrete floors that would form the new structure to which the original brick façade would be secured.
I know about this because having seen the scaffold collapse broadcast during that news programme I was, some 20 months later, instructed to act as expert in defence of the hapless architect who was being sued for alleged incompetence and negligence in the matter. And so it was that I came to learn a little about the various types of scaffolding design used in the UK which are usually assembled from tubular steel, connecting fittings and timber boards – as opposed to continental Europe where ‘system scaffold’ assembled from modular units is preferred; or China and India where I have marvelled at the extraordinary use of bamboo scaffold, even for high-rise projects.
Herein, within the British scaffold industry, lies a wonderful world of components: single couplers, double couplers, swivel couplers, pin couplers, sleeve couplers, band and plate clamps, girder clamps, swivel girder clamps and so on – but I digress.
The important point for the purposes of this story is that there are principally three types of scaffold arrangement adopted here:
- Self-supporting with lateral stability provided by building.
- Self-supporting with lateral stability provided by raking shores.
- Cantilevered off building (i.e., no ground support).
The scaffold in question had been of the first type; that is, self-supporting off the pavement in front of the building, deriving its lateral stability from the façade.
All had gone well with the project until the contractor’s team removed, as part of a phased demolition programme, the party walls that had hitherto restrained the front façades. Anyone who has worked on such buildings knows that such ‘connections’ can, at best, be tenuous as Victorian builders often used a relatively poorly skilled bricklaying team for the party walls (which would be concealed by plaster and could be ‘rough’), other better skilled gangs for the rear elevations, and their most skilled bricklayers for the frontages. Such work practices inevitably led to sequencing delays where the bonding of party and front and rear elevations was less effective than would otherwise be the case had they been built simultaneously but, Hey Ho, that was the way they worked.
The problem here was, of course, that when even that lesser tying in of the partially connected party walls was rendered ineffective through demolition, the roles of the front façade and the scaffold were, in structural terms, reversed: the scaffold which had hitherto derived lateral support of the street elevation was now required to provide that support, albeit off a wholly inadequate base.
As the workers smashed out the latter parts of the party wall they heard a loud bang, and fearing for their safety, scrambled out of the site and raised the alarm. The street was of course closed and cordoned off, crowds gathered, and the press arrived in good time to see the entire wall swaying in the wind until, just in time for that night’s News at Ten, down it all crashed.
So, I hear you ask, ‘what had all this to do with the architect?’ Well, read on……..
The losses were substantial and led to a heavy claim against the D+B Contractor; you know the stuff: escalation of work, abortive work, major contract overrun, L+A Damages and all that….and no doubt claims from local traders for losses during the street closure, and even the Council. As would be expected the builder co-joined the scaffolder who pleaded ignorance of the fact that the façade was to ever have been left unsupported, but it all shook down in the end to a defence on the contractor’s side that the external wall was adequately constructed to remain stable in its own right during the works, but could not carry the lateral load of the scaffold; and on the scaffolder’s side, that that method statement for scaffold erection and restraint had been clear from the outset: it was to be provided throughout by the wall.
And indeed, in that respect, there it was: a clear method statement that supported the scaffolder’s position. So, next came the second line of defence from the builder: the scaffolder’s method statement had anyway been passed to the Project Manager who had approved it. In, therefore, was dragged one of London’s major QS companies that had masqueraded as the Project Manager, howling and squealing as normal that they were only shuffling paper and were neither qualified to know, and indeed did know, nothing about anything.
The QS/Project Manager’s defence was that they had passed the method statement for scaffolding to the architect, and as he had not responded they had assumed all had been checked and was well….that having hitherto driven his fees through the floor.
Happily, we got the architect off, but it was a close-run thing, and therefore offers a significant lesson for us all: don’t let Project Managers, or anyone else for that matter, just send you stuff willy-nilly. This is particularly important in these days of easy copying of emails and the massive overload of information flows. Instead, instruct your teams to root out all such correspondence and, without fail, send it back, making clear that such work lies outside your scope of service and responsibility. In the alternative, agree to provide the checking required if you are qualified so to do, but get paid for it! Boring task I know, but a lot more fun than spending hours in litigation.
Indeed, with the new Building Safety Act coming live, it is more important than ever before that you limit your responsibilities to whatever they should be under contract, and that against them, you perform as you should.