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Explanation of the Cost Tables
This
manual provides construction or
replacement costs for a wide
variety of residential,
commercial, industrial,
agricultural and military
buildings. For your convenience
and to avoid possible errors,
all the cost and reference
information you need for each
building type is listed with the
primary cost figures for that
building. After reading this and
the following two pages you
should be able to turn directly
to any building type and make an
error-free estimate or
appraisal.
The costs
are per square foot of floor
area for the basic building and
additional costs for optional or
extra components that differ
from building to building.
Building shape, floor area,
design elements, materials used,
and overall quality influence
the basic structure cost. These
and other cost variables are
isolated for the building types.
Components included in the basic
square foot cost are listed with
each building type. Instructions
for using the basic building
costs are included above the
cost tables. These instructions
include a list of components
that may have to be added to the
basic cost to find the total
cost for your structure.
The
figures in this manual are
intended to reflect the amount
that would be paid by the end
user of a building as of mid
2007.
They show
the total construction cost
including all design fees,
permits, and the builder's
supervision, overhead, and
profit. These figures do not
include land value, site
development costs, or the cost
of modifying unusual soil
conditions or grades.
Building Quality
Structures
vary widely in quality and the
quality of construction is the
most significant variable in the
finished cost. For estimating
purposes the structure should be
placed in one or more quality
classes. These classes are
numbered from 1 which is the
highest quality generally
encountered. Each section of
this manual has a page
describing typical
specifications which define the
quality class. Each number class
has been assigned a word
description (such as best, good,
average or low) for convenience
and to help avoid possible
errors.
The
quality specifications do not
reflect some design features and
construction details that can
make a building both more
desirable and more costly. When
substantially more than basic
design elements are present, and
when these elements add
significantly to the cost, it is
appropriate to classify the
quality of the building as
higher than would be warranted
by the materials used in
construction.
Many
structures do not fall into a
single class and have features
of two quality classes. The
tables have “half classes” which
apply to structures which have
some features of one class and
some features of a higher or
lower class. Classify a building
into a “half class” when the
quality elements are fairly
evenly divided between two
classes. Generally quality
elements do not vary widely in a
single building. For example, it
would be unusual to find a top
quality single family residence
with minimum quality roof cover.
The most weight should be given
to quality elements that have
the greatest cost. For example,
the type of wall and roof
framing or the quality of
interior finish are more
significant than the roof cover
or bathroom wall finish. Careful
evaluation may determine that
certain structures fall into two
distinct classes. In this case
the cost of each part of the
building should be evaluated
separately.
Building Shapes
Shape
classification considers any
cost differences that arise from
variations in building outline.
Shape classification
considerations vary somewhat
with different building types.
Where the building shape often
varies widely between buildings
and shape has a significant
effect on the building cost,
basic building costs are given
for several shapes. Use the
table that most closely matches
the shape of the building you
are evaluating. If the shape
falls near the division between
two basic building cost tables,
it is appropriate to average the
square foot cost from those two
tables.
Area
of Buildings
The basic
building cost tables reflect the
fact that larger buildings
generally cost less per square
foot than smaller buildings. The
cost tables are based on square
foot areas which include the
following:
- All
floor area within and
including the exterior walls
of the main building.
- Inset
areas such as vestibules,
entrances or porches outside
of the exterior wall but
under the main roof.
- Any
enclosed additions, annexes
or lean-tos with a square
foot cost greater than
three-fourths of the square
foot cost of the main
building.
Select the
basic building cost listed below
the area which falls closest to
the actual area of your
building. If the area of your
building falls nearly mid-way
between two listed building
areas, it is appropriate to
average the square foot costs
for the listed areas.
Wall
Heights
Building
costs are based on the wall
heights given in the
instructions for each building
cost table. Wall height for the
various floors of a building are
computed as follows: The
basement is measured from the
bottom of floor slab to the
bottom of the first floor slab
or joist. The main or first
floor extends from the bottom of
the first floor slab or joist to
the top of the roof slab or
ceiling joist. Upper floors are
measured from the top of the
floor slab or floor joist to the
top of the roof slab or ceiling
joist. These measurements may be
illustrated as follows:
 Square
foot costs of most building
design types must be adjusted if
the actual wall height differs
from the listed wall height.
Wall height adjustment tables
are included for buildings
requiring this adjustment. Wall
height adjustment tables list
square foot costs for a foot of
difference in perimeter wall
height of buildings of various
areas. The amount applicable to
the actual building area is
added or deducted for each foot
of difference from the basic
wall height.
Buildings
such as residences,
medical-dental buildings,
funeral homes and convalescent
hospitals usually have a
standard 8-foot ceiling height
except in chapels or day room
areas. If a significant cost
difference exists due to a wall
height variation, this factor
should be considered in
establishing the quality class.
Other Adjustments
A common
wall exists when two buildings
share one wall. Common wall
adjustments are made by
deducting the in-place cost of
the exterior wall finish plus
one-half of the in-place cost of
the structural portion of the
common wall area.
If an
owner has no ownership in a
wall, the in-place cost of the
exterior wall finish plus the
in-place cost of the structural
portion of the wall should be
deducted from the total building
costs. Suggested common wall and
no wall ownership costs are
included for many of the
building types.
Some
square foot costs include the
cost of expensive veneer
finishes on the entire perimeter
wall. When these buildings butt
against other buildings,
adjustments should be made for
the lack of this finish. Where
applicable, linear foot cost
deductions are provided.
The square
foot costs in this manual are
based on composite costs of
total buildings including usual
work room or storage areas. They
are intended to be applied on a
100% basis to the total building
area even though certain areas
may or may not have interior
finish. Only in rare instances
will it be necessary to modify
the square foot cost of a
portion of a building.
Multiple
story buildings usually share a
common roof structure and cover,
a common foundation and common
floor or ceiling structures. The
costs of these components are
included in the various floor
levels as follows:
The first
or main floor includes the cost
of a floor structure built at
ground level, foundation costs
for a one-story building, a
complete ceiling and roof
structure, and a roof cover. The
basement includes the basement
floor structure and the
difference between the cost of
the first floor structure built
at ground level and its cost
built over a basement. The
second floor includes the
difference between the cost of a
foundation for a one-story
building and the cost of a
foundation for a two-story
building and the cost of the
second story floor structure.
Location Adjustments
The
figures in this manual are
intended as national averages
for metropolitan areas of the
United States. Use the
information on page 7 to adapt
the basic building costs to any
area listed. Frequently building
costs outside metropolitan areas
are 2% to 6% lower if skilled,
productive, lower cost labor is
available in the area. The
factors on page 7 can be applied
to nearly all the square foot
costs and some of the
"additional" costs in this book.
Depreciation
Depreciation is the loss in
value of a structure from all
causes and is caused primarily
by three forms of obsolescence:
(1) physical (2) functional, and
(3) economic.
Physical
obsolescence is the
deterioration of building
components such as paint,
carpets or roofing. This
deterioration may be partially
curable. The tables on pages 43,
205 and 239 consider only
typical physical obsolescence.
Individual judgments will have
to be made of functional and
economic obsolescence.
Functional
obsolescence is due to a
deficiency or inadequacy in some
characteristic of the building,
such as too few bathrooms for
the number of bedrooms, or some
excess, such as a 10 foot
ceiling in a residence. This
obsolescence may be curable. The
tables do not include functional
obsolescence considerations.
Economic
obsolescence is caused by
factors not directly concerning
the structure, but rather, by
adverse environmental factors,
resulting in loss of
desirability. Examples include
the obsolescence of a store in
an area of declining economic
activity, or obsolescence
resulting from governmental
regulation changing the zone of
an area. Because this kind of
obsolescence is particularly
difficult to measure, it is not
included in the tables.
“Effective
age” considers all forms of
depreciation. It may be less
than chronological age, if
recently remodeled or improved,
or more than the actual age, if
deterioration is particularly
bad. Though effective age is not
considered in the physical life
tables, it may yield a better
picture of a structure's life
than the actual physical age.
Once the effective age is
determined, considering
physical, functional and
economic deterioration, use the
percent good tables on pages 40
or 200 to determine the present
value of a depreciated building.
Present value is the result of
multiplying the replacement cost
(found by using the cost tables)
by the appropriate percent good.
Limitations
This
manual will be a useful
reference for anyone who has to
develop budget estimates or
replacement costs for buildings.
Anyone familiar with
construction estimating
understands that even very
competent estimators with
complete working drawings, full
specifications and precise labor
and material costs can disagree
on the cost of a building.
Frequently exhaustive estimates
for even relatively simple
structures can vary 5% or more.
The range of competitive bids on
some building projects is as
much as 10%. Estimating costs is
not an exact science and there
is room for legitimate
disagreement on what the "right"
cost is. This manual can not
help you do in a few minutes
what skilled estimators may not
be able to do in several hours.
This manual will help you
determine a reasonable
replacement or construction cost
for most buildings. It is not
intended as a substitute for
judgment or as a replacement for
sound professional practice, but
should prove a valuable aid to
developing an informed opinion
of value. |
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