CONCRETE FOR HOUSING

Hauraki Plains Gazette, Volume XXXV, Issue 4786, 8 December 1924, Page 4

CONCRETE FOR HOUSING

VIEWS OF AN ENGLISH EXPERT. ADVANTAGES OF PRE-CASTING. Tile advantages ur concrete ad a building material, are strongly emphasised in an informative article contributed recently to the London ‘'Observer’’ by Professor S. M. Dixon, -'it Imperial College, South Kensington. The former prejudice of architects against concrete as a material of construction especially for domestic architecture, Professor Dixon remarks, is rapidly passing, and now that various economic conditions are pushing concrete forward as a substitute for bricks in housing schemes it will be found that a material can be produced which possesses to a higher degree than any ether the numerous qualities which should be found in any good building, stone or brick. While mass concrete possesses great strength and durability and other excellent qualities, in some respects it iS( not satisfactory for housing. Economically, houses cast in moulds can only be successful if immense numbers are turned out according to the same design. American engineers have long recognised the advantages of pre-cast concrete. Comparatively light sections, besides being stronger and more durable when built of pre-cast members, are more easily controlled during manufacture, and m construction tnfere is no wastage of timber or steel in the forms needed for mass concrete. Even reinforce.l concrete work is frequently pre-cast, the various pieces being later lifted together. In housing the same organisation 01 the building trades is required wheii concrete blocks are used as in the case when the walls are of brick, and, when well-designed and manufactured blocks are used, there is no trouble with labour.

Leaving generalities, it will be well to specify some of the principal qualifications of a building material for domestic architecture, and see howconcrete, especially in the form of blocks, will possess these qualifications. For housing purposes the building material should be durable, impervious to moisture, suflicineUy strong, a non-conductor of heat, pleasing in appearance, not too costly, and easily worked by available labour. Concrete, pre-cast in suitably designed building blocks, possesses these qualificationis in a higher degree than any other building material. Except granite, some marbles, and sandstones, and one or two varieties of bricks hardly obtainable on account of cost, concrete is the most durable of all building materials. Cement mortar is constantly used to preserve stone buildings already falling into

decay owing to weathering. Again, concrete, properly proportioned. is impervious to moisture. Watci-pipes 'and tanks can be made absolutely watertight, even under considerable pressure, without any waterproofing material. This fact must be insisted on, .since discredit has bee i brought on concrete by hastily-con-structed and . hadly-propoitioned socalled concrete. The strength of concrete leaves nothing to be desire.!, and may be designed to suit any requirements by simply varying the propifrtio'ins of cement and aggregate. As a non conductor, solid concrete is not so good as bricks, but concrete block, can be made hollow, and then the walls are non-conducting, and, of course much more so than solid bricu walls. Many architects insist on hollow b.ick walls, and in small houses with these walls difficulties arise in the construction which can be entirely obviated with some types of concrete block construction. Concrete buildings can be seen near London which show no condensation during the severest weather changes. This question of noil-condensation is very important, as many houses with isolid masonry walls have gained a bad reputation in the damp winter climate of Great Britain, and it is a most satisfactory result of considerable experimental work that concrete houses properly built show no condensation under most trying conditions. It will be noted that such houses will be warm in winter and cool in summer, owing to tae protective effect of the non-conducting air spaces in the walls.

While much mass concrete in or Hie well-known dull, uninteresting greenish-grey colour, it is a very easy matter to tint concrete in a permanent fashion, especially when made m blocks. Indeed, by selecting the aggregate most pleasing, yellow-browns of various shades may lie obtained, and a waii built of such blocks shows a pleasing want of isamencss. Various pigments may be used to give desired effect., the amount used being too small to affect materially the other qualifies of the concrete. Many variations m the surface texture of the block may be obtained either during moulciing or after setting. Long experience in these matters in the United States allows architects here (in great Britain) to follow those various processes, for the experimental stage in finishing and surfacing concrete is long past. As in other engineering matters, cost of materials for housing should be one of the prime considerations, and here, again, it will be found that concrete blocks compare most favourably with bricks, and are, of cqurso, much cheaper than 'stone. The cost of real concrete blocks must be com-pir-ed witli that of the best building bricks. Inferior bi’ickp possess few of the requirements of a.good build-

ing material, and so must be covered with roughcast or rendered with mortar—a most unsatisfactory proceeding, since, in many cases, the deterioration of the brick proceeds almost as fa t a.’ if exposed to the weather, and after a few years the roughcast '>r mortal' 11. dies oIT. - it is true that in some caiscs cement houses arc roughcast, but' lliis is only necessary, when Hu inferior, porous concrete is used, and is a needless expense witli real concrete.