A good mixture for the second or finish coat is made in the proportions of one part domestic Portland cement, one part shell lime, and five parts of clean white marble dust. This dust should not be the refuse of a marble quarry, but should consist of clean white marble spe cially ground for stucco work. This coat should be allowed to dry slowly, being dampened if necessary, similarly to the undercoat.
It is essential that the casings, cornice, base, and beltings be so made that the plaster shall be keyed to it. Strips of wood for the English half-timber effect are beveled on their edges as indicated in Figs. 90 and 91. Casings may be similarly beveled on their outer edges except the head, which is tinned so as to turn the water. A more common method of making casings is to run a moulding entirely around the casing, allowing it to project over the outer edge about five-eighths of an inch. Such casings have an "apron" similar to that used on the inside.
Metal and Wood Lath. The question of the relative merits of metal and wood lath is one that does not seem to be fully settled. In fact, both metal and wood have their advantages and their disadvantages. Time will tell. At pres
ent both are used in about equal proportion, each having advocates with very decided opinions.
The advantage most frequently urged in behalf of metal lath is its rendering the wall fireproof. Its greatest disadvantage is its lia bility to rust. This disadvantage, it is claimed by manufacturers, is overcome by having the lath back-plastered so that the meshes are com pletely embedded. This does not fully protect the metal, however; and to overcome the diffi culty, metal lath galvanized or coated with pro tective paint is being placed on the market.
The advantages and disadvantages of wood lath are too well known to the reader to need repeating. The poor quality of the lath now generally found on the market, which is becom ing poorer from year to year, and their liability to shrink, warp, and buckle, render them far from ideal. The decrease in their width, with the consequent more frequent clinches, and their cheapness, have served to keep wood lath to the front in the outlying districts where fireproof ing is not so much insisted upon.