Walls inside of cellar should continue to the top of joist. This completely separates the different compartments of the cellar, or from that part of the house where there is no cellar.

There should be a man-hole opening to the parts under the house where there is no cellar.

Lintels or wooden supports should be provided over all openings in cellar, and over all openings in inside brick walls.

Wooden brick should be provided and built in where it is necessary to attach wood work to brick work. Usually this is about two feet six inches apart in a vertical or horizontal direction. The wooden brick should be the thickness of the brick itself and the mortar joints; that is, there should be no mortar above or below a wooden brick. Iron ventilators should be provided; one in each outside wall under each room where cellar windows are not provided. Windows are not usually provided where there is no cellar.

CHIMNEYS.

It is known that wood-work should not come directly in contact with chimneys. The framework should never rest on a chimney. There are reasons for this other than those which have a regard for safety from fire, one of which is that the chimney is not liable to settle. If it does not, the shrinkage of the wood-work, which in a two-story frame house will sometimes amount to two inches in the height of the building, makes a high place around the flues, where the frame comes in contact with or rests on the chimney. All chimney-stacks should extend above highest point of ridge of roof, and the extreme tops should be laid in Portland cement. All the exposed brick of the chimney should be hard-burned. If due regard were paid to these points, there would be no rickety chimney-tops. All flues should be thoroughly plastered on the inside. If chimneys were plastered on the outside, wherever they come in contact with the wood-work, the complaint of fires from defective flues would be hushed.

[Fig. 31] illustrates the common form of constructing a chimney breast where a grate is to be used. The flues are eight and one-half inches square. A passage to the ash-pit is shown. The grate opening is two feet wide; the jambs on each side are one foot six inches wide; thus the entire width of the breast is five feet. Other dimensions as indicated. Where there are grates on two floors of the house, one above the other, or where it is desirable for any reason to have a flue pass around a grate, it is necessary that the breast should be five feet wide. It is clear that the grate from below must have its own flue out to the top of the chimney. Thus the grate flue from the first story must pass around the grate of the second story, if there be one. If there is no grate above, or if it is not desired to pass a flue around the first-story grate, the chimney breast need be only four feet wide; that is, it would have the usual two-feet opening to the grate, and twelve rather than eighteen inch jambs on each side. On one side of the dotted line is indicated flue construction for a brick wall, and on the other for a wood wall.

The hearth should rest on what is called a trimmer arch, which is made of brick. It springs from the chimney breast to the header of wood in front. It is four inches in thickness. It is laid in the ordinary way, and at the proper time is filled on the top with concrete by the mantel-setter. In case a grate on the second floor connects with the ash-pit, one of the flues at the side is used for this purpose.