Unit 10 Foundation Prints 173
Footings must rest on undisturbed earth
below the frost line, the deepest point to which
the ground will freeze in a given region. The local
building code will give the depth of the frost line,
and how far below it the bottoms of the footings
must be placed.
Steel reinforcing rods are placed in the foot-
ings. This is especially important when footings
must pass over earth previously disturbed due
to an earlier excavation. When a poured con-
crete foundation wall is to be erected on the
footing, the drawing may call for a keyway to
be cast in the footing to anchor the wall. Refer
to Figure 10-1.
On a foundation plan, footings are shown as
hidden lines, Figure 10-3. The width of the foot-
ing under the foundation walls and columns
is shown. Reinforcing rods are shown as dots
and solid lines in sectional views. On elevation
drawings, these rods are indicated by solid lines
showing how the rods are laid out. In addition,
notes on the drawing and in the specifi cations
must be carefully checked for details relating to
construction of the footings.
Foundation Walls
Foundation walls are the base of the build-
ing. They transfer the weight of the building to
the footings and to the ground below. Foundation
walls can be poured-in-place concrete or concrete
masonry units (concrete block). Poured-in-place
concrete is used where soil and weather condi-
tions exert considerable side pressure on the
walls. Where feasible, the use of concrete masonry
units is an effi cient way of constructing a founda-
tion wall, because no forms are required. Usually,
Concrete wall
Concrete wall
footing
Wall beam spanning
wall footings
Top of footing elevation
TOF=91'-4"
Concrete
column
Column
footing
Pilaster Top of footing elevation
TOF=89'-4"
Footing steps
Figure 10-3.
A partial foundation plan showing footing and wall locations.