Bricks Of Loess And Cement

Press, Volume CVIII, Issue 31568, 4 January 1968, Page 8

Bricks Of Loess And Cement

Mr R. J. M. Loughnan, of 61 Ayn e s Street, Rangiora, is building a house which he believes may be unique in New Zealand— the bricks are made of loess and cement.

Mr Loughnan said that some houses in Kennedys Bush Road, Halswell, were built with loess clay, but had been constructed by ramming the clay into shutters. The first house using this principle was built in Lower Riccarton in 1945 by Mr P. J. Alley, a retired lecturer in soil mechanics at the University of Canterbury.

Mr Loughnan is achieving j two of his ambitions —to build a house with his own hands—and to own a house which, he says, he could never otherwise have afforded. The house he is building is on a section facing the White Street extension, in Rangiora. Loess is a wind-blown clay material of a very fine texture. For building purposes, the loess must contain no decayed vegetable matter. Large quantities of loess are found at the west end of the Port Hills, and that used for Mr Loughnan’s house was collected near Halswell. When compressed, the clay has no tendency to spring back. It erodes quickly but if mixed with Portland cement this characteristic is altered. The mixture will absorb water, but will not pass it through. It is a form of concrete., says Mr Loughnan.

At first the mixture has a consistency like wood, but after about 12 months of hardening a nail can no longer be driven into it. About 6 to 7 per cent of cement and 10 per cent of water is used to make a cohesive mixture.

The clay is compressed in a ram, designed in Mexico. The ram works on a double lever principle. In normal production runs, 20 tons pressure is applied to the clay through a pressure of 1001 b on the leverage linkage system of the machine. This allows the box in which the brick is moulded to be compressed from a capacity of 12in by 6in by 6in to a depth of 4in. The machine also ejects the completed block. Blocks Tested

The Soil and Cement Laboratory at the School of Engineering of the University

of Canterbury carried out several experiments on blocks selected at random. A brick weighing 13.131 b had a density of 98.151 b a cubic foot Tests showed the brick collapsed at a pressure of 11,9001 b, and had a loadbearing weight of 2871 b a square inch. A “special” brick, which had been subjected to twice the compression in the making, weighed 14.61 b and had a density of 107.411 b a cubic foot During the experiments, the brick collapsed at 27,4001 b, and thus had a loadbearing weight of 6481 b a square inch. About 5000 bricks have been used in the walls of the house, which are Bft 6in high. Hand screening the clay from a stockpile at the depot of a Rangiora transport firm and carting it by trailer, Mr Loughnan has averaged an output of up to 150 bricks a day. All work has been done by Mr Loughnan, his family and friends, in spare time, since the project was started two years ago.

The method of using loess went back to early Roman times, said Mr Loughnan, who has adapted the style of architecture of the house to suit the material. The house has a roof area of 2350 sq. ft, and will have 1850 sq. ft of living space. Window frames are of aluminium alloy, and apart from facia boards and a back door, no timber will face the weather. The house will probably have a conventional roof. The foundations and concrete floor were also laid by Mr Loughnan. Top-soil under the floor was scraped away, and the area filled with 80

yards of shingle. The foundations were built Sin above ground level. The excavated soil was placed between the road frontage and the house, giving an effect of the house being set into a higher section.

The frontage is retained by a stone faced wall, 83ft long and 2ft high. Constructed of boulders from the Ashley River bed, the fence was built in two months leisure time.

Mr Loughnan expects to finish the house by the winter.

The photograph shows Mr Loughnan working on his new house.