331. Probably 99 per cent of modern buildings, in this country at least, have plastered walls, ceilings and partitions. It is only lately, however, that much attention has been given to this branch of building operations, and there is probably no doubt but that much of the plastering done at the present day is inferior to that done fifty or one hundred years ago.

The introduction of fireproof construction and the desirability of completing large and costly business buildings in the shortest possible time has shown the necessity for improvements in the materials used both for the lathing and the plastering, and several new materials have been introduced to meet the demand.

Even in dwellings it is important that the finish of the walls and ceilings shall be as nearly perfect as possible, as large sums of money are not infrequently spent on their decoration, and it is therefore essential that the ground work shall be so durable that the decorations will not be ruined by broken walls or falling ceilings. The quality of the workmanship is also of much importance, as nothing mars the appearance of a room more than crooked walls and angles, and dents, cracks and patches in the plastering.

To secure a good job of lathing and plastering it is essential that only the best materials be specified and used, and that the mortar be properly prepared and applied. These can only be insured by being careful to specify exactly how the work shall be done and the materials that shall be used, and supplementing the specifications by efficient supervision. In order to furnish such specifications and superintendence, it is obviously necessary that the architect shall be thoroughly familiar with the materials used and the way in which they should be applied.