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Chapter 17 Constructing Structures
The framework can be built out of three
different materials. See Figure 17-12. Small
and low-cost buildings have frameworks
made from lumber. Most industrial and
commercial buildings have either steel or
reinforced concrete frameworks. Building
the framework involves three steps.
Floors
First, the floor is constructed. See
Figure 17-13. Homes with slab founda-
tions use the surface of the slab as the floor.
Those with basements or crawl spaces use
lumber floors.
Lumber floors start with a wood sill
bolted to the foundation. Floor joists are
then placed on the sill. They extend across
the structure. Floor joists carry the weight
of the floor. The span (distance between out-
side walls) and the load on the floor deter-
mine the size and spacing of the joists. On
top of the joists, a subfloor is installed, usu-
ally made from plywood or particleboard.
After the building is enclosed, flooring
material is installed on top of the subfloor.
Figure 17-11. This worker is excavating a
hole for a pool.
Figure 17-12. The materials used for framework are lumber, steel, and reinforced
concrete.
Lumber Reinforced Concrete Steel