The face of the wall was composed of blocks, as described, and rough concrete thrown in to complete its thickness, and that of the counterforts. After a frost it was found that this wall was seriously damaged, hardly a single block having escaped, and in many cases their whole face had peeled off to the depth of half an inch. The discharge of a drain from a height of 6 or 8 feet had worn away the lower courses to the depth of some inches. On a like wall at Chatham, similar but much more severe effects were produced.
The failure of this wall costing about 80,000l., was a serious matter, and for several years after architects looked upon concrete as being so much uneatable hasty pudding, considering that it was only beneficial when confined in a trench for foundations. Sir Robert Smirke used it in the foundations of the Penitentiary, Millbank, and Sir John Soane in 1830 used it in the foundations of the New State Paper Office (now pulled down) in St. James’s Park. Here the ground had to be excavated to a depth of 22 feet before arriving at a gravelly stratum; at each high tide the Thames filled the trenches with water, which remained in considerable quantity; as this was pumped out, the adjoining party walls of the buildings in Duke-street cracked so completely that they had to be taken down. The trenches were first filled to the height of two feet with broken stones and bricks from the old buildings, and then dry lime and clean river sand, with a large quantity of small broken granite stones, were thrown in from the height above. A body of concrete 8 feet in width by a thickness of 3 feet was thus formed; the water ceased to enter the trenches and the building was commenced.
Mr. G. Godwin, the editor of the “Builder,” in an essay on concrete which gained the first prize given by the Royal Institution of British Architects, appears to have been the first to suggest its use in walls above ground; and for these Portland cement concrete, when properly prepared, is without question an admirable material.
DESIGN No. 7.
A garden gate—plan and elevation.
In France it is used to a very great extent, in numerous bridges, and several miles of large sewers. A church (that at Vésinet, near Paris, of mediæval architecture), constructed entirely with iron and this concrete, is completely fireproof. In England a considerable length of sewer has been constructed of concrete at Sidmouth, under the direction of Mr. Phillips; and near London, between the Kensington and Gloucester Road stations of the Metropolitan Railway, a very large handsome bridge, rusticated, and in design similar to, and in every respect in appearance a stone bridge. From some alteration required in the railway, it has been removed.
This mode of construction is now being practically tested in the north of England, at Church Bank, Alnmouth, in its complete form, in a cottage built entirely of concrete, having three rooms, scullery, and other conveniences. The material used in the building, as we are told by the “Builder,” is Portland cement and gravel from the sea-shore. The foundation is in sand 6 inches thick and 18 inches wide; in this there is a base course, and above, the walls are 9 inches in thickness. Part of the erection is two stories in height. The roofs are all flat, and are constructed entirely of concrete and old wire rope. The ceilings are divided into panels by ribs at right angles, and require no plastering. A wall on the upper floor is supported by a concrete beam with a 13-feet span; and a large cistern is formed under the roof of the pantry for rain water. The sides of the cistern forming the walls of the bedroom will test severely the impermeability of the material. No wood is used except for doors, and no iron except five shillings’ worth of old wire rope. This is said to be an experiment made by the Duke of Northumberland.
Another experimental cottage has been constructed under Mr. Edwin Chadwick’s superintendence at East Sheen near Mortlake. In this the walls are formed of light iron framework filled with compressed straw, bitumen, and concrete. The thickness of each wall complete is only about three and a half inches. The floors are of bitumen and concrete, covered with ordinary deal boards; the roof has the same construction as the walls. These, inside, may be either left rough or finely smoothed, without additional cost. In the former case it is said they resemble the ordinary “dashes” of stuccoed cottages; in the latter they appear as if coated with Roman cement, after the fashion of villas and town houses.