FLOOD07624

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Basin: Statewide
• Title: Raising and Moving the Slab-on-Grade House
• Date: 1/1/1990
• Prepared For: State of Colorado
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

INTRODUCTION

Approximately seven percent of the
land area of the United States is subject to
flooding from one source or another~ Unfor-
tunately, because of their locations near water,
the areas subject to flooding have been, and
continue to be, highly desirable for human
habitation and development. As a result,
much of the nation's population and industry
is located in flood prone areas, and has suf-
fered tremendous losses from flood damage.
Many approaches to flood protection
and flood loss reduction have been developed
and used with varying degrees of success,
including raising existing structures above
expected flood levels, or relocating them to
flood free areas. Those particular approaches)
are relatively simple for structures originally
constructed on piers; however, they are not as
well recognized as economically viable
practices for structures on concrete slab
foundations. In the case of slab foundations,
there are, however, two practical possibilities:
detaching the structure from the floor slab, or
moving the entire structure with the slab
attached. The latter practice, moving the
entire structure with the slab attached, is not
widely known and understood and is often
believed to be infeasible. It is, however,
technically feasible, is often economically
feasible, and presents many advantages in the
hands of an experienced structural mover.
The purpose of this report is to discuss
the procedures for raising or relocating' 'slab-
on-grade" structures with the slab attached, to
point out some of the advantages and disad-
vantages, to suggest some factors to consider,
and to indicate the possible costs involved.
The procedures and techniques described here
are based primarily on those employed by a
professional structural mover currently operat-
ing in the Tampa Florida area. Other profes-
sionals in the field may employ different but

equally effective methods. No undertaking of
this magnitude should be attempted without
the advice and assistance of professional
structural movers and structural engineers or
arcitects.

RAISING AND RELOCATING

Raising a structure above expected
flood levels or relocating it to a flood free area
are both effective flood damage reduction
measures. Both are relatively expensive
however, and each has advantages and disad-
vantages.
In many instances a particular home
site is selected for the aesthetic values pro-
vided by proximity to water, either a stream or
shoreline, without recognizing the flood
potential or in spite of it. In such cases,
moving the home to a flood free site would
not be the preferred solution even if possible.
In other cases the site is relatively unimpor-
tant, but moving the structure to a new site
presents insurmountable difficulties either
because of the route involved, or because of
the lack of an alternate site within a reason'"
able distance. In such cases raising the struc-
ture in place may be practical.
Some possible disadvantages to raising
in place compared to relocation include: the
possibility of escape routes being blocked by
rising flood waters; damage and disruption to
necessary utilities; the possibility of greater
flood heights than designed for; the possibility
of a false sense of security. The relocation of
a structure has fewer disadvantages for the
individual property owner, assuming a free
choice to relocate or not and a reasonable
selection of alternate sites. One notable.-,_'.,;:
disadvantage, however, is that a structure of
any appreciable size must usually be separated
into sections small enough for the transporta-
tion route involved, then reassembled at the

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