The ceiling of the cellar should be below ground level sufficiently to
bring it below the level of frost. For the regions where bees should be
wintered in cellars this usually will be at least 2-1/2 feet below the
level of the ground (fig. 3). The ceiling should be 6-1/2 feet above
the floor, just sufficiently high to permit a tall man to work with
comfort. If the ceiling is higher it will result usually in too low a
temperature at the floor. The ceiling then should be covered completely
on top with some insulating material, such as sawdust, and if sawdust
is used it should be piled on about 1-1/2 feet thick. Unless about this
amount of protection is given on the ceiling it will be impossible to
get the right cellar temperature during the coldest part of the winter.
If the cellar is built in a sandy soil, it is possible to use the soil
as a cover for the ceiling, in which event about 3 feet of soil should
be placed over the inner roof of the cellar. The entire insulating
material, of whatever kind used, should then be protected from rain
and snow by having a roof over it. This roof should project at least
2 feet, preferably more, beyond the outside of the cellar wall, and
provision should be made for currying off the water from the roof.
In case the beekeeper desires to build an apiary house over the bee,
cellar, as is done frequently, he must provide a floor for this house
at least at ground level, and he can not successfully use the ceiling
of the cellar as the floor of the upper house. There is no objection to
building a house above the cellar if adequate protection is given the
cellar, but it must not be assumed that the house offers any material
insulation to the cellar, for in most cases these houses are not heated
in the winter. The relation of the house floor to the ceiling of the
cellar is shown in figure 3.