185. Plaster grounds, as explained in Art. 123, are simply nailing strips secured to the studs for receiving the trim; they consist of strips of wood from 5/8 inch to 1 inch in thickness, according to the character of the plastering, and in width they vary from 2 inches to 3 inches, according to the purpose they are to serve.

In the angle formed at the meeting of the stud partitions and the rough floor, a strip 1 in. X 2 in. is nailed to the studs, and a similar strip is nailed about the height of the baseboard above and parallel to it. To these strips the base is then nailed after the plastering is dry.

In dining rooms, kitchens, billiard rooms, etc., where a chair rail, or wainscot, is to be placed, another ground about 4 inches wide, is nailed to the studs 2 feet 6 inches to 3 feet above the floor, according to the height of the wainscot, and in parlors, libraries, reception rooms, etc., a strip 1 inch in width is nailed from 1 foot to 2 feet 6 inches below the ceiling to receive the picture molding. This latter strip is not generally used, as the picture molding may be placed directly on the surface of the plaster, wire nails being driven in the studs or furring strips, or into wood plugs in case of brick partitions. Where a wood cornice is to be carried around a room, a ground must be provided for it in the angle between the ceiling and the side walls.

The surface of the stud partitions between these grounds are then lathed. The ceilings in ordinary work are lathed directly on the under side of the beams, but where a first-class job is desired, the beams should be cross-furred, as explained in Art. 126.

186. The interior of the house is now ready for the plasterers, but the carpenter should shingle the roof before the plasterer's work is started, in order to protect the walls and ceilings in case of rain. The shingling should be started as soon after the roof is covered in as is possible, and according to the methods previously explained.