The hearth should be about flush with the floor, for sweepings may then
be brushed into the fireplace. When there is a basement, an ash dump
located in the hearth near the back of the fireplace is convenient. The
dump consists of a metal frame about 5 by 8 inches in size, with a plate,
generally pivoted, through which ashes can be dropped into a pit below
(fig. 35).
[Illustration: Figure 35.--The ash-pit should be of tight masonry and
should be provided with a tightly fitting iron clean-out door and frame
about 10 by 12 inches in size. A clean-out for the furnace flue as shown
is sometimes provided.]
In buildings with wooden floors the hearth in front of the fireplace
should be supported by masonry trimmer arches (fig. 34) or other
fire-resistant construction. Hearths should project at least 16 inches
from the chimney breast and should be of brick, stone, terra cotta, or
reinforced concrete not less than 4 inches thick. The length of the
hearth should be not less than the width of the fireplace opening plus 16
inches. Wooden centering under trimmer arches may be removed after the
mortar has set, though it is more frequently left in place. Figure 36
shows a recommended method of floor framing around a fireplace.