“The mode of setting the bars and arranging the work on each successive elevation of the casing is to cut on the surface of the completed part of the wall a groove 1 in. wider than the bar, filling it in, after placing the bar, with sand, to the level of the wall’s surface. The side boarding being set up, the vacant space left along the bevelled edge of the previous course is filled up with moist clay to retain the first layer of the new course. The end pieces are secured by iron bars or rods, with screws and nuts.”[7]
Ramming.—“Gentle and quick ramming has been found most effectual.”
Report on the Pisé-work executed at the Etah Jail during 1867-8. By Mr. H. Sprenger, Assistant Engineer
“The boxes in which the pisé-work at the Etah Jail is being executed consist of two wooden frames 10 ft. long and 2½ ft. broad, made of planks, which are nailed on to stout battens. They are held together by four pairs of posts 3 in. by 3 in., which are connected above and below with tie-bars of flat iron 1½ in. by ¼ in. The tie-bars have at each end a certain number of ½ in. holes punched in them to receive pins for the purpose of preventing the posts from slipping off. By changing the pins, walls of any given dimension can be obtained, wedges of hard wood, with longitudinal slots, are introduced between the posts and the pins, to adjust the breadth of the boxes to a standard gauge. After the boxes are fixed and adjusted, they are secured in their position by ropes passing over them, and tied to stakes on each side. Any deflection from the vertical should be corrected at the commencement of the work, as it is impossible to alter the position of a box after it is half full. Any earth which is suitable for brick-making will do for pisé-work. On being dug out it is passed through a screen with ½-in. meshes, and thrown into the boxes in even layers of 6 in. in depth.
The Right Quantity of Water
“Generally fresh earth contains sufficient moisture to ensure good consolidation; but if it is found that it jumps up under the rammers, it should, on being thrown into the boxes, be sprinkled with a little water out of a tin can with a rose. The watering should be as uniform as possible, as if it is applied unequally it will liquefy the earth, which will commence oozing out under the rammers. Pisé-work executed with too much water is worse than if done with dry earth, as, on account of the elasticity of the wet earth, the effect of the ramming is deadened, and the earth remains unconsolidated. The men should be prohibited to keep time in ramming, as it causes vibration, which is injurious to the stability of the wall. On working over a lower course, it is as well to let the lower tie-bars about 4 in. into the same to give the boxes a firm hold on the old work, thereby the joints become imperceptible, and the upper edge of the lower course is prevented from chipping off.
“The implements used are three different kinds of rammers. The earth is first beaten down with a V-shaped rammer, and then surfaced with one with a flat bottom. The sides of the boxes are consolidated with a spade-shaped rammer. When commencing the pisé-work at Etah, considerable difficulty was experienced in extricating the lower tie-bars. These were, therefore, supplied with holes 3 in. apart throughout their whole length. A pin was inserted, against which a crow-bar with a long slot and well bent at the end was made to work. An equal pressure could thereby be exerted against the tie-bars; they were thus extracted with great facility without injuring them or the face of the wall, which was not the case formerly.”
Supplementary Note by Mr. E. Battie, Executive Engineer, 5th Division, Grand Trunk Road
“The work at Etah has generally been concluded in the following manner: In the morning the boxes were taken down, and again put up and filled during the day; they were left during the night, so that the earth might detach itself from the sides. It is not advisable to allow a course to dry thoroughly, as the upper one will not bind well into it, but probably show a crack. If the earth is well rammed, and only the proper quantity of moisture admitted, a second course can be commenced immediately.”
The Report of the Rhodesia Munitions and Resources Committee issued in 1918 contains an interesting paper by Mr. John Hynd on Pisé-building, from which the following is extracted: