Transcript 35 - School District of Rhinelander

Chapter
35
Estimating Building Costs
Objectives
• Explain the process of estimating the building
cost for a residence.
• Prepare a preliminary estimate of the cost of a
residential structure using the square foot or
cubic foot method.
• Generate a final estimate for a simple structure.
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Permission granted to reproduce for educational use only.
Introduction
• Estimating is an organized effort to determine total
cost of materials, labor, and other services
required
– Made after house has been designed, construction
drawings completed, specifications prepared
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Permission granted to reproduce for educational use only.
Preliminary Estimates
• Preliminary estimate created at design stage
– Estimates probable costs and to place limits
• Design contingency indicates how much cost
overrun may occur on project
• Two manual methods of estimating building costs
are square foot method and cubic foot method
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Square Foot Method
• Estimate based on total area of house
– Compute number of square feet in house
– Multiply square footage by constant value,
determined by local conditions
– Garages, porches, basements figured separately, at
about one half of living area cost
– Square footage determined by multiplying house
length by house width
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Square Foot Method Example
• 24' x 60' house, 20' x 20' garage
– Living area 1440 square feet, garage 400 square
feet
• $100 per square foot building cost for living area
– 1440 x $100 = $144,000
• $50 per square foot building cost for garage
– 400 x $50 = $20,000
• Total cost: $144,000 + $20,000 = $164,000
• Price of land not included
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Cubic Foot Method
• Based on volume of house
– Volume found by multiplying area by height
– Height is distance from floor to ceiling for each level
of house including basement
– Attic volume included, calculated by multiplying
area by 1/2 of rise
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Cubic Foot Method Example
• 24' x 60' house
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–
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–
Living area 1440 square feet, height 8'
1440 x 8 = 11,520 cubic feet in living area
Attic area 1440 square feet, rise 4'
1440 x 2 = 2880 cubic feet in attic
Total volume is 14,400 cubic feet
• $10 per square foot building cost for living area
– 14,400 x $10 = $144,000
– Total building cost for house, $144,000
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Cubic Foot Method Example
• 20' x 20' garage
– Volume
400 x 8 = 3200 cubic feet
– Garage attic rise,
3' feet, 400 x 1.5 = 600 cubic feet
– Total garage volume, 3200 + 600 = 3800 cubic feet
• $5 per square foot building cost
– 3800 x $5 = $19,000
• Total estimated building cost, $144,000 + $19,000 =
$163,000
• Price of land not included
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Employability
• Entrepreneurship
– Entrepreneurs are people who start and run their
own businesses
– Work for themselves, feel a sense of
accomplishment, can be financially rewarding
– Entrepreneurs do their own work, plus all the work
for the business (marketing, accounting)
– Do your research before committing to
entrepreneurship
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Green Architecture
• Costs of green building design
– Initial building costs for green building are higher
than costs for traditional construction
– An experienced estimator can help a client build a
sustainable home for little more than traditional
building costs
• Keeping up-to-date on available products, processes,
and guidelines allows estimator to provide green
solutions that may not increase cost of home
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Final Estimates
• Preliminary estimates can vary considerably from
actual cost
• More accurate cost estimate is final estimate, or
material takeoff
• Created by outside company specializing in
estimation
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Permission granted to reproduce for educational use only.
Materials Estimate
• Estimator compiles list of materials required
• Once listed and priced, total material cost
calculated
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Labor Estimate
• Can range from 60% to 89% of total building costs
• Costs vary widely throughout United States
• Use publications that provide detailed information
regarding labor costs for various areas of country
• General contractors and subcontractors can also
provide help in projecting costs
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Other Costs
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•
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Insurance
Fees for permits
Environmental impact fees
Other fees
Once evaluation of costs is complete, total building
cost can be calculated
– Variations from preliminary estimate may be due to
materials price fluctuations, labor overruns
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Computer Estimates
• Software programs for estimating save time
– Floor plan is imported, analyzed, and costs are
automatically calculated
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Permission granted to reproduce for educational use only.
Computer Estimates
• Estimate for electrical work required on a
residential construction project.
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.
Organizing Estimates
• Organized according to work breakdown structure
(WBS)
– Common systems are MasterFormat and
UniFormat
• UniFormat system more commonly used for
preliminary estimates
• MasterFormat system used for final estimates
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Permission granted to reproduce for educational use only.
MasterFormat System
• Numbered divisions and titles identify construction
requirements, products, activities
• Not all divisions apply to residential construction
• Some divisions reserved for future use
• Divisions are organized under groups and
subgroups
© Goodheart-Willcox Co., Inc.
Permission granted to reproduce for educational use only.