This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
These are made by ramming cohesive earth into a mould. The earth selected should contain no stones larger than 1 cub. in., and those which are admitted must be of a rounded form. No organic remains liable to decay must be present. The insistence and degree of moisture of the earth should be carefully regulated in accord-ace with the conditions proved by experiment to be best adapted for securing the most perfect cohesion of the mass. The foundation for an earth wall should be a few courses of brick or stone. To erect an earth wall on this, recourse must be had to a mould, after the manner of concrete building. The construction and arrangement of such a mould re illustrated in Fig. 1418. The joists a, 4 in. wide and 2 1/2 in. deep, are laid on the foundation wall b at intervals corresponding to the lengths of the boards forming the sides; on their upper face near each end a mortice is cut for the reception of the uprights d, at points allowing afficient width for the boards e and a breadth of arth wall c equal to that of the foundation wall b below. The uprights d, which tenon into the ists a below and the cap pieces f above, should e about 30 in. high in the clear.
Inside these prights d, are fitted edge to edge, and united by tongues or pins, a series of 1-in., clean, well-seasoned pine boards e, not exceeding 14 ft. in length, while half that figure will often be more 3nvenient. To strengthen the boards, they have attens nailed across them, outside, at intervals of about 30 in., and iron handles may be attached or facilitating removal. The wedges g are for le purpose of tightening the cap j on the up-rights d, and adjusting the width of the wall. angle moulds for the corners of walls may be made on exactly the same principles. Where a wall is intended to end abruptly, a ead is put into the mould by fastening strips of batten to the boards e and dropping a head board. In commencing to build, a few courses of brick are carried up with the ists a built in, so as to give rigidity to the mould; as the wall rises, the mould is taken part for further use, the joists being driven out endwise, for which purpose they are lade slightly tapering. When the first mould in height has been completed, recesses must be cut to admit the joists for the nest stage. The use of the plumb level is of course as necessary with this as with any other kind of wall.
In ramming the earth, a depth of 3-4 in. at a time is always enough, and the strokes should travel from the sides towards the centre and from one end to the other, leaving the end sloping where the next addition is to be made. In building the second course, care should be taken that the joists fall between the joist holes of the preceding course, and the ramming should . commence from the opposite end of the wall. The joist holes may be afterwards filled up with wooden blocks, for convenience in fastening the internal fixtures, and wooden joists may be built in lengthwise at intervals. The rammer should weigh about 14 lb. Unfinished work should be kept covered from the rain.