Artist's drawing of a community of cocoons
mandrel. Then the core, in the form of panels of polyurethane, is placed over the inner skin and finally the outer skin of filament is wound over the core. The mandrel is then removed from inside the shell.
It was estimated that if these units were constructed at a fixed central plant and then transported to the building site, the size would be limited to 12ft. wide which would not result in satisfactory house plans. However, it would be economically possible to use a transportable factory if a com- munity of 100 houses or more were to be produced. It was estimated that the cost of setting up, dismantling and transporting a mobile factory within a radius of 200 miles would be US$10,000.
Assuming present winding speeds, it was determined that for efficiency in shell production the field winding equipment should comprise two turn- tables and four mandrels. This would allow good co-ordination of the fila- ment winding with the other shell production operations.
Based on present technology, pro- duction on a three-shift basis is es- timated at four 36 x 20 x 8 ft. shells a
day, or two houses assuming two shells per house. With minor develop- ment work the speed of production could be doubled. In this event the shell production and the other opera- tions involved in the proposed building system could be co-ordinated to the point where four finished houses would be produced daily.
plete the housing units would be pre- fabricated and installed in the struc- tural shells before the housing units are moved to their final location. The estimated weights for the housing unit shells would present no major lifting problem even in the use of existing construction equipment, even if doubl- ed by including the interior elements. For example, a 20 x 32 x 8 ft. shell weighs 8905 lb.
Materials for the end walls of the shells have been selected for low main- tenance and ease of assembly. They consist of lin. thick sandwich panels with reinforced plastic skins and po- lyurethane foam core, 4in. plate glass and aluminium window sashes and doors. These components are attached to the shell by using a structural neo- prene zipper gasket which is both mechanically fastened and bonded to the shell.
Reinforced vinyl-faced gypsum wall-board panels were chosen for the interior partitions. Partitions are at- tached to the shell with a mechanically fastened butyl zipper gasket. Doors and frames are integral with the sys-
tem.
Flooring
The floor presented the most dif- ficult sub-system problem. The de- cision to accept for the time being a uniform curved cross section for the shell requires that a non-structural floor be added to obtain a flat floor surface. A non-structural floor also permits easy installation of ducts,
All components required to com- pipes and wires.
The most promising solution calls for a partly foam supported ABS or vinyl surface with integral duct-ways and vacuum-formed surface guides for the positioning of partitions. Initially the floor can also be built of 5/8-in. plywood supported on a light open steel frame.
Bedroom closets, kitchen cabinets and other storage elements are pre- fabricated modular units constructed of high-density urethane foam and vacuum-formed ABS plastic. Bath- rooms are moulded reinforced plastic units.
These shell units can be joined to- gether in various ways, either end-on, side-by-side or one above the other to make houses of varying volume.
An elaborate cost analysis has come up with the conclusion that, as- suming a yearly production rate of three- and four-bedroom housing units with an average floor area of 1260 sq. ft., the average projected cost per unit would be US$19,200. This is eight per cent less than that of present military family housing of equal size.
Says Professor Paraskevopoulos in his report: "The proposed building system based on filament winding has many of the ingredients necessary to achieve high quality housing at lower cost. However its successful introduc- tion and application hinges on certain conditions that have to be recognised and dealt with. The satisfaction of these conditions is crucial for the system does not offer
panacea but a solution requiring both investment and careful planning."
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Far East BUILDER, May 1970
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