SupportingColumns Repairordemolish? Brian Morton admits that there are times when repair does not seem possible. When faced with an historic building in a state of collapse, the Engineer has to make immediate decisions as to whether repair is possible or if demolition and rebuilding as a facsimile is a reasonable proposition. In this article, I have described our work at 28 Market Place, Stockport but a reference to a building in Spitalfields in London is worthwhile because on occasions it is necessa1y to accept that intrusive structural support systems are necessary to retain a particular element of a construction - in this case a facade. At a property in Brushfield Street Spitalfields, part of a Georgian terrace, I explained to our client, The Spitalfields Trust, that the facade of this three storey building was distorted to such an extent that it could not be saved using traditional methods and I felt that rebuilding was the only solution. I was advised by the Trust that this elevation was one of the earliest in Spitalfields and it would accept intrusive repair proposals. Photograph l: The building was shored on two elevations and there was no support for the shoplront bressumer. We devised a very light steel frame comprising 100 X 100 mm square hollow sections to form, effectively, a grillage behind the elevation, and used stainless steel resin anchors to anchor the brickwork back to it. Although this steel frame was initially exposed internally, the Client felt that it was acceptable to batten out with timber and expanded metal lath and plaster to cover this intrusive structure. Of course, it meant that the window recesses were deeper than original, but it was felt that this was acceptable. Surprisingly, the solution turned out to be cheaper than a traditional rebuilding or repair solution because it simply provided a diaphragm to restrain the wall and fix back to the floors with no requirements for foundations for this structure. I have assisted the Metropolitan Borough of Stockport with regard to two Georgian buildings and one cruckframe building on the Market Place. Context60 December1998 Normally these buildings when originally seen would have been writtenoff if it were not for Jean Fricker, the Conservation Officer, making a stand. At the point of our involvement we felt that the three buildings were in a condition where they could be restored with care, but as time went on it became apparent that the structure of No 28 Market Place was in a perilous condition. As can be seen from photograph 1, the building was shored on two elevations and there was no support for the shopfront bressumer. The walls were seriously distorted throughout and the roof covering had been stripped. We were able to cany out a fairly detailed survey and produced a Schedule of Works describing exactly the extent of the works necessa1y. At this stage, all was fairly straightforward - then there was a fire. Timber floor beams and parts of the roof structure, which were still, in some cases, rounded timber, were seriously affected. The gable wall, some three storeys high, partially collapsed and was left free-standing. The collapse of walls occurred inwards, the timber floors collapsed and there was a very real danger to anybody attempting to go into the building. At a meeting with the Borough Council, I expressed doubts about the possibility of saving the remainder of the structure particularly because of the CDM Regulations (Health & Safety at Work Act). Nevertheless, we thought we would proceed on the basis of an initial clearing out contract followed by a structural repair contract. In considering the clearing out, it was not possible to send anybody into the building. One of our engineers was dropped clown in a bucket from a crane to enable him to assess the situation. Based on this rather precarious survey, we produced a brief schedule which described how elements of the structure would need to be removed from the top downwards and lowered, or dropped down in some cases, into the centre of the building. The Planning Supervisor, under the CDM Regulations, assessed the risks and the contractor produced his safety plan describing his proposed methodology for carrying out the work. Our engineer had been able to establish which walls were 'live' and 29
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