BRICKWORK AND EARTHQUAKES

Evening Post, Volume CXIV, Issue 120, 17 November 1932, Page 10

BRICKWORK AND EARTHQUAKES

(To the Editor.) Sir,—ln a letter to "The Post" of the 10th November, Mr. Stanley Natusch, achitect; commenting on Mr.-W. H\ Bennett's recent talk with a "Post" reporter, attributed the failure o£ brickwork in the Hawkes/Bay earthquake partly, at least, to the use of limestone sand in the cement mortar. - He states that "the destruction of brickwork so built reveals the fact that the unburnt lime in the sand reacts on the cement, depleting the mortar of its strength." If such is the case, it is most important to know the nature of the reaction and how it was determined. Limestone sand has been used long, enough and universally, and indeed is recommended by. authorities for use. in mortar. If this sand is a mixture of clay or loam and lime, then one can understand that it would be injurious,, but unburnt lime, that is calcium carbonate; such as could, originate from hard chalk, Oamaru stone, marble, etc., is quite harmless, inert, and has_ no other effect than that of economising cement, as do other sands used for mortar. . Probably, the failure might be -traced to the quantity rather than the quality of the sand. . With a long experience .of building, I entirely agree witn Mr. W. H. Bennett' that the widespread destruction of brickwork by the earthquake was due firstly to bricks having 'been laid too dry;-secondly, to the use of lime mortar; and I may add a thirdly— the scant, inefficient -filling of vertical joints so usual with the majority of "expert" bricklayers aiflicted with the speed craze: The primary essential is that bricks ought to be laid saturated, not merely sprinkled with a hose, once or twice a day. Particularly is this essential in a dry, warm climate.like that of Hawkes Bay.—l am, etc., ~:.\ .". JOHN" CAMPBELL, ' ' Architect (retired).