THE DAY OF CHANGE

Evening Post, Volume CIX, Issue 125, 29 May 1930, Page 10

THE DAY OF CHANGE

ARE MAKESHIFTS BEST?

BUILDING AND ECONOMY

Unknown developments in industry and science have left builders of all kinds in a state of uncertainty. The following extract from the report of the Division of Highways in California gives food for thought:— "There has been an increased number of redwood and creosoted Douglasfir bridges built during the past two years. For several years the great majority of l short-span bridges on the State highways have been built of concrete. They were built for permanent structures, but the large, unlooked-for increase in traffic and the much higher standard of alignment now in use on the connecting .highways have rendered many of these bridges, with narrow roadways and poor alignment of approaches, either dangerous or very unsatisfactory for present-day conditions. Where the bridges are narrow, but on good alignment, the defect can be remedied by widening the structure, and this has been done in many cases; but where the alignment of the approaches is poor it frequently happens that this cannot bo corrected without abandoning the existing bridge altogether. It has thus developed that many of these so-called permanent bridges have become obsolete in less than ten or fifteen years. Assuming a thirty-five-year life for a creosoted fir or redwood timber bridge, and neglecting tho fire hazard, the timber bridge will in most cases be slightly cheaper in the long run than a permanent concrete structure, the saving in first cost being more than enough to rebuild the timber structure at the end of thirty-five years. Tho disadvantages of the timber strueturo are the firo hazard and the inconvenience to traffic at tho time of rebuilding, j When the available funds for any bridge project are limited, there is therefore no loss in economy in building a timber structure, and where there j is any doubt as to the permanency of location for a crossing a timber bridge is obviously the economical type." PERMANENCE UNNECESSARY, j Permanence in utility buildings is no longer the important factor it once was, because the changes in demands have been so marked during the last decade that it is difficult to tell just what will be wanted in twenty years. There is, therefore, no wisdom in building some structures in brick or reinforced concrete, for tho reason that they will be inadequate, or wrongly-designed, for tho needs of a comparatively near future, and when they come to be pulled down,- the more expensive material of which they were constructed spells a double waste, being harder to dismantle and moro durable (and more costly) than the probable life of the building warranted. This point, brought out in regard to various public works, applies also in private construction, with the -possible exception of homes, and even here fashions change so much with tho advent of fresh discoveries for tho comfort of man that ten-year-old homes are out of date. Fortunately for this aspect of the question, most of the dwellings in New Zealand are of wood, which permits reconstruction readily where the material has survived the attacks of insect pests and decay, but there is a loss in tho perishable building, just as there is in the' permanent oue that has to be demolished, and a fortune awaits thov inventor of tho permanent, adaptable building. Some form of keyed building block, with a non-adhesive mortar sufficiently coherent and resilient to stand the pressure of: several stories, would <it least enable the same material to be used twice or more, and would avoid the loss caused by demolition, always falsely saddled on the natural increment of land valuta, . ,