FLOOD07643

• County: Statewide
• Basin: Statewide
• Title: Physical and Economic Feasibility of Nonstructural Flood Plain Management Measures
• Date: 3/1/1978
• Prepared For: US
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

j~~'

-- --.

-=<
,
,
l
t
\
.
l
i
(
i
\
i
\
I,
i
l
(
\
\
,
\
\
(
t
(
'.

;
~
t
,
':
(
(
\
l
(
(
i
i
,
(
,.
\
i
,
I
,.
I
i
(
,;
"
I'
,.
I
,
I
\
~

does not protect the basement and it is doubtful many basement walls or floors could be
reinforced to take the hydrostatic head economically. A more likely approach if it were
necessary to raise a structure with basement would be to minimize the damageable property in
the basement and allow flooding. Brick, brick veneer, and masonry structures, while heavier
and more difficult to handle can also be rqised. Structures with concrete slab floors on the
ground (slab-on-grade) and structures with common walls (row structures) are not feasible to
raise without special equipment and additional expense. While it is physically possible to raise
many types of structures, it is often not practical for the reasons mentioned above. Where
raising in-place is in fact being done it seems to be principally to wood frame type structures on
raised foundations (no basement).

As to height of raising, residential structures have been satisfactorily raised up to nine feet (1).
Aesthetics, intended use, 100 year flood elevation and structural stability are factors which often
influence the height selected. Generally the additional cost to raise a structure an additional
foot or so is small compared to the initial set-up cost.

Costs
Base cost items to raise a structure in-place include,

· Brace, jack, and reset structure (including disconnecting utilities and temporary
connections).

. Extend existing or construct new foundations.

. Extend and reconnect all utilities.

· Reconstruct walks, steps, ramps.

· Relandscape site (including plant replacement and siding).

. Architectural/Engineering fees.

Additional cost items may be applicable depending upon the specific site conditions.
Examples of these items include,

· Removal and disposal of sidewalks, curbs, ramps, driveways not used in the reconstruc-
tion.

. Updating structure foundation and utilities to code.

· Additional bracing for stucco, or brick sidings or structures in poor condition.

. Reconstruction of chimney and fireplace.

· Temporary housing during raising.

. Additional aesthetic work.

Engineer's cost estimates were made for raIsing a 1600 square foot structure without
basement, on a raised foundation, three feet. These data are summarized in Table 4-1. Only base
cost items were included so the estill)ate would represent a minimum cost. The Table shows a
total estimated first cost of $7,750, and an annual cost of $621. As a percentage of total structure
value for a $30,000 structure the annual cost is 2.1 percent. Lesser valued structures may cost less
to raise, either because they are of smaller size, or simpler architecturally. However, because
they are of lesser value the lower cost may be offset and the percentage remain the same.

23