Laying the Groundwork
It is
important to know your home's foundation type, even though you may
never see it, as part of building an overall knowledge base about your
home. The foundation of a house is its anchor to the earth. It
provides the base and the initial dimensions for the structural frame
and is a necessary preliminary for every phase that follows, including
finishes. The foundation outlines the footprint of your
home. Although it may be invisible to you, knowing about the
foundation of your home will enable you to take responsibility for its
care and maintenance. It is essential to know your existing
foundation type if you are thinking of a remodeling project --
especially one involving a room addition -- in order to determine how
the new space will tie into the old. There are three primary foundation
systems for single-family homes in the U.S. These systems include a
full-height basement (perhaps finished), a crawl space (the main floor
structure is raised a few feet off the bare ground), and a flat
concrete slab at ground level. In some cases, a large room
addition to an existing home may have a different foundation than the
original structure. Cost, the requirements of building codes, design
or floor plan features, or the necessary accommodation of mechanical
equipment and their distribution conduits are factors that determine
the choice. Second-story additions, may require upgrades to existing
foundations in order to carry the extra weight (or "load") of the new
upstairs section. In spite of their differences (described in more detail
below), all foundation types have two major features in common. First,
a foundation of any kind requires a footing to properly anchor it --
and the home above -- to the ground. Footings are usually shafts
filled with concrete at each corner of the foundation's footprint,
poured to a depth determined by the local building
code. Second, all foundations are reinforced to boost their
strength and durability. This is usually done with steel rods called
reinforcement bar, or "rebar" for short. Like footings, the number,
size, and placement of rebar in a foundation system is prescribed by
code. Basement Foundations. A basement foundation is
selected when there is a very deep water table below the house, when
the home site is on a sloping lot or when the owners want the option
of additional living space below the main living area. Typically built
with reinforced poured concrete or stacked concrete blocks, basements
are usually full-height to allow everyday use, even if just for
storage or the placement of mechanical equipment. If the house is
built on a hill, the exposed side or sides of the basement may allow
for windows and perhaps a door (called a "walk-out" basement),
providing natural light and access to the below-grade part of the
basement. Crawl Space Foundations. A crawl space sounds
just like what it is: a foundation in which the walls that form the
perimeter of the house are about 3 feet high, spanned across by the
structural floor framing materials. The result is an unfinished
(though usually insulated) area under the house populated by duct runs
from the heating and cooling equipment, plumbing pipes, electrical
wires or conduits, and other system components serving the living
spaces above. Also called a "raised floor" system, a crawl space
allows convenient (if tight) access to those systems and the
structural floor members for periodic maintenance, repair, inspection,
or upgrades. Slab Foundations. Literally, this is a thick slab
of reinforced poured concrete with deeper footings embedded at the
corners. The slab creates a stable platform for the home's structural
frame. Set directly on or slightly into the ground ("on grade"), a
slab foundation is typically selected in flat dry areas where digging
into the ground is not possible or financially feasible. The
monolithic platform created by this type of foundation is ideal for
tile floors and carpet. The slab also provides an effective thermal
mass, absorbing heat during the day and releasing it at night to
maintain a comfortable -- and inexpensive -- indoor climate, another
reason for its popularity in desert areas. There are several less common
foundation systems, as well, including insulated concrete forms and
permanent wood foundations. However, basement, crawl space, and slab
foundations are the prevailing types. Knowing what's under your house
can be a valuable piece of knowledge down the road as you consider
future remodeling projects.
Warm regards,
 
Dwight
Sailer & Bryan Soth
HighCraft Builders
429 S. Howes Street
Fort Collins, CO 80521
970.472.8100 - phone
info@highcraft.net
www.highcraft.net
c.
2008
All rights reserved.
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