Demolition blasts back at our latest diatribe.
Yesterday morning, we sent out the latest edition of This Week in Demolition, our weekly round-up of news, views, jobs, video and comment (if you don’t currently receive it, give us your details at the top right-hand side of this page).
The subject to fall under our spotlight this week was unseen voids and basements or, rather, the demolition industry’s apparent inability to find them before they swallow another excavator.
But E. Nicholson commercial manager Craig Black was having none of it. Instead, he penned the impassioned response (below) to set the record straight. We have reproduced Craig’s response with his permission:
I’m not necessarily disagreeing with your comments regarding unseen voids but you’d be surprised just how easy and frequent the discovery of such voids are.
We’ve carried out umpteen contracts through which basements/sealed chambers/underground culverts and all sorts of voids are found during demolition process.
The primary reasons for failure to locate pre-contract are: –
a) Biggest failing in the industry – The clients rarely provide record drawings for existing structures.
b) Record drawings – Often they are incomplete or unavailable and it normally costs us money to try and obtain the same. Under CDM it’s the clients duty to provide this info.
c) Unrecorded Voids – The older the structure the less chance there is of having a fully documented history of building alterations etc.
d) The void didn’t originally belong to the structure in question – Wouldn’t be the first time we’ve uncovered chambers etc from buildings that were demolished previously and then subsequently built over.
e) Mine Workings – Irrespective of record drawings held we’ve found that mines are often poorly recorded or in some instances not at all. We’ve also seen SI reports which have missed mines with boreholes falling just outside the perimeter of mine shafts. It’s very much hit and miss doing an SI.
f) GPR Surveys – Great if you’re on open land. Crap if you’re trying to find out what’s below a building.
So, I don’t think it’s very fair of you to place this at the door of the demolition contractor. We know more than most when it comes to this sort of thing and short of developing X-Ray vision it’s always going to be a problem until such time that we start receiving complete H &S files for buildings. This if course won’t happen for around another 20 years or so given that the requirement to produce such info was only enforced in the late 90’s onwards. If a building is due to come down within that time, I say ‘Shoddy builder’ or emergency works.
Just thought I’d add my tuppence worth.