These, like all details, depend on the size and purpose of the
building. The method of setting a small building on posts has been
explained under poultry house, and sheltered seat for tennis court.
It should be used only for small structures, such as camp buildings,
sea-shore cottages, and out-buildings. Brick, stone, and concrete all
have their advantages, but for young builders, concrete is perhaps the
best and easiest to handle. The woodwork necessary for concrete work is
extremely important, and its possibilities have hardly been touched,
even to-day. The box or form should present the smooth side of the
boards to the concrete, and should be so constructed that the form may
be readily removed after the concrete has hardened. This sounds like a
simple matter, but it becomes complicated in many cases. The method of
fastening the wooden frame to a concrete foundation is suggested in the
chapter on the making of a pergola. In some houses the frame is simply
laid on the concrete, and the weight of the building is trusted to keep
it in place.
In the case of small structures this would not be sufficient, and a
better way would be to imbed bolts in the cement before it hardens.
Pass these bolts through holes bored in the sill, and fasten them with
nut and washer on top, after the concrete has hardened.
Any foundation should be sunk at least three feet in the ground,
otherwise it will be "heaved" by the frost. Where a cellar is to be
built, the foundation should be of sufficient depth to leave at least
6 feet 6 inches in the clear between floor of cellar and under side of
floor beams, and seven feet would be better. If the foundation extends
two feet above the ground, its bottom would be 5 feet 6 inches below
the ground level.
The thickness of the concrete wall must depend on the size and weight
of the building, and for a small cottage it should not be less than
ten inches. The columns described for the pergola make an excellent
foundation for a small building to be placed on posts, as they do not
decay and are permanent. They may be used to advantage for porches in
place of wooden posts.
After a building is completed, some of the top soil removed in digging
the cellar should be graded up to the foundation at a slight slope,
to shed the rain and carry it away from the building. The box for a
concrete wall should be well supported and braced, as the weight is
sufficient to force the boards out of position. The method shown at
Fig. 226 is frequently used, the 7/8 or 1 inch plank being supported
by 2 × 4 inch studs, which in turn are braced as shown. On cheap work
the outside boarding is omitted, the earth being shaved with the shovel
as near the position of outer casing as possible. Of course, this
earth wall is only useful within a foot or so from the surface. At this
point the outer boarding must commence, and be continued to top of
foundation. In order to have the foundation level on top, it is best
to level the wooden form all around the four sides. If the concrete is
brought exactly to the top, and a straight edge is run along the edges
of the form, the resulting wall must be level, provided the box has
been made so. Concrete does not flow enough to level itself.
[Illustration: Fig. 226. Concrete foundations]