t-
Fig. 10. Demoulding beam with block and tackle running on rails. Note standard clamps and latches between battery units
non-loadbearing and are faced with a dark red glazed tile. On the short facades the cladding is structural and has a horizontally-ribbed surface.
All cladding slabs are cast face- down in horizontal moulds which are placed along two sides of the site. Because of the shape of the panels. the window becomes part of the ver- tical panel-to-panel joint, and halves the normal joint height. The rain- water build-up is also reduced. Wea- ther-proofing depends upon an open. two-stage joint with one fixed and one loose neoprene strip, and the joint material is replaceable. But the win- dows cannot be cast into the panels under this arrangement.
For insulation, a layer of expanded polystyrene is fixed to the inner face of the solid cladding panels by gal- vanized nails, pushed into the con- crete before the initial set. After erection, plasterboard is stuck on to the polystyrene, and finished with paper. This insulation ensures that no heat is used to warm up the
Fig. 11. Prepacked fittings are hoisted to working area
cladding in cold weather, but the in- sulation must also be an effective vapour barrier if condensation is not to occur at the panel.
The foundations of the building are piled, and a basement of in-situ con- struction provides space for car park-
The fully-precast superstructure begins at the ground floor. During erection all fittings, partitions, dry lin- ings and equipment for each flat are prepacked and hoisted into the dwell- ing area (Fig. 11) before it is covered by the next layer of floor slabs.
Cost Considerations
It seems that the cost performance of this technique is very promising. When compared with in-situ casting, battery casting of wall panels shows savings of about 50 per cent in man- hours and 25 per cent in costs.
For floor panels, the man-hour savings of 25 per cent are equalled by the cost of extra steel required, so the net costs for battery and in-situ
casting are similar. Perhaps the most impressive figures found so far are those for man-hours including produc- tion and erection of all structure and
cladding. which are 300-350 per dwelling or about 2,000 per storey.
In other terms this type of work may be seen as an operational inven- tion, and as such may be applied to component-based, open systems. It has proved a practical proposition for the smaller contractor, and has shown that the widely-publicised 'knowhow of heavy prefabrication, at least to current technical standards, may be relatively easily acquired by men hav- ing the usual range of traditional building skills.
In conclusion, it should be pointed out that this method of battery cast- ing may have a variety of applica- tions. It should be possible, for in- stance, to accommodate a number of different jointing methods, provided that the detailing is considered in re- lation to the production problems within the battery.
Also, although the particular ap- plication outlined in this article relates to site casting for tall blocks of flats where maximum numbers of units are required within crane reach of the batteries, the method could well be used for lower blocks the units in this case being distributed horizontally from a central casting area.
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Fig. 12. Edmonton block in progress
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All photographs used in this
feature are
Crown Copyright
Far East Architect & Builder August, 1966
Page 60Page 61
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