CON-499 · Lesson 5 of 12 · 20 min

The estimate and the bid

Bid day for Pembrook Fire Station No. 3 started at 6:30 in the morning and ended at 2:00 in the afternoon, when the town clerk stamped the last envelope. In between, the Tamarack team received sixty-three subcontractor prices, found two mechanical quotes that excluded work the others included, lost the low electrical price when its bidder withdrew at 12:40, and changed the bid total four times. Ruth signed the bid form at 1:41. Owen said later that the four hours before the deadline were the most intense of his career, and that they would have been impossible without the six weeks of work that came before them.

This lesson covers the fifth deliverable: the estimate and the bid. It builds on estimating and bidding (CON-300) and uses the scope from lesson 2, the procurement plan from lesson 3 and the quantities from lesson 4. For a capstone, the estimate must be complete, organized, traceable to its quantities and quotes, and honest about its markups and contingency.

The structure of a contractor's estimate

A contractor's estimate for a stipulated price bid has four layers. Direct costs are the cost of the work itself: labor, material and equipment for self-performed work, and subcontractor prices for the rest. General conditions, sometimes called site overhead or general requirements, are the costs of running the site that do not belong to any one trade: supervision, the site office, temporary services, cleaning and similar items. Contingency covers pricing risk that the estimator cannot remove. Markups cover bonds, insurance, head office overhead and profit. The bid is the sum of all four.

Horizontal bar chart of the seventeen trade divisions in the Pembrook estimate, sorted from largest to smallest, with concrete, electrical, HVAC and metals at the top
Direct trade costs by division. Five divisions make up more than half of the direct cost.

Owen organized the direct costs by MasterFormat division, because that is how subcontractors quote and how the town's schedule of values form was arranged. Each line carried the WBS code from lesson 2, so that the estimate could later be turned into a schedule-linked budget.

Summary of direct trade costs in the Pembrook estimate.
DivisionCostSource
03 Concrete$1,480,000Concrete subcontractor quote plus Tamarack tower formwork
04 Masonry$620,000Masonry subcontractor quote
05 Metals$1,150,000Steel quote plus miscellaneous metals
07 Thermal and moisture$940,000Roofing, insulation, air barrier, sealants
08 Openings$690,000Overhead doors, hollow metal, glazing, hardware
09 Finishes$780,000Drywall, flooring, painting, ceilings
22 and 23 Plumbing and HVAC$1,850,000Mechanical subcontractor quote
26 Electrical$1,320,000Electrical subcontractor quote including generator
31 to 33 Earthwork, exterior and utilities$1,690,000Site works subcontractor quote and Tamarack estimate
Other divisions$1,380,000Wood, specialties, equipment installation, fire suppression, alerting rough-in
Direct trade cost$11,900,000

Pricing self-performed work

For the work Tamarack would do with its own crews, Owen priced labor from quantities, productivity rates and labor rates. A labor rate starts with the wage and adds the employer's costs on top of it.

Worked problem

Building up a loaded labor rate

A carpenter's base wage is $36.00 per hour. Payroll taxes and insurance (Social Security and Medicare, federal and state unemployment taxes and workers' compensation insurance) add 22 % of wages, and fringe benefits add $9.40 per hour. What is the loaded hourly rate?

Show solution
  1. Payroll taxes and insurance: $36.00 × 0.22 = $7.92.
  2. Fringe benefits: $9.40.
  3. Loaded rate: $36.00 + $7.92 + $9.40 = $53.32 per hour.
  4. The loaded rate, not the wage, is what goes into the estimate, along with an allowance for small tools and consumables.

Answer: About $53.32 per hour.

Productivity came from Tamarack's records of similar work, adjusted for site conditions. Forming the training tower's footings and walls, for example, was priced at 0.051 crew-hours per square foot of contact area, slower than the company average because the tower was small, tall and needed many corners and openings. The tower had 4,410 ft² of contact area, so the formwork labor was about 225 crew-hours.

General conditions

General conditions are often underpriced by students and by contractors in a hurry, because they are not shown on any drawing. They depend mostly on time: a 14-month project pays for a superintendent, a site office and temporary services for 14 months. Owen priced them month by month from the schedule Tomas was building in parallel, then checked the total against Tamarack's history for similar projects, where general conditions usually ran between 5 % and 7 % of direct cost.

General conditions for 14 months, equal to about 5.6 % of direct cost.
ItemBasisCost
Superintendent14 months × $13,500$189,000
Assistant superintendent and field engineer12 months × $9,000$108,000
Project manager at 60 %14 months × $7,200$100,800
Project coordinator at 50 %14 months × $3,300$46,200
Site office, trailers, furniture and IT14 months × $3,100$43,400
Temporary power and water14 months × $1,800$25,200
Temporary toilets and safety supplies14 months × $1,500$21,000
Winter heat and hoardingLump sum$68,000
Cleaning and waste bins14 months × $2,600$36,400
Small tools, survey and layout14 months × $1,200$16,800
Fencing and signageLump sum$17,200
Total general conditions$672,000

Analyzing subcontractor quotes

Most of the estimate came from subcontractors, and the main skill on bid day is comparing their quotes fairly. Subcontractors rarely quote exactly the same scope. One excludes fire stopping, another excludes the controls, a third includes the extraction system connections that the others assumed someone else would do. Bid leveling, or scope leveling, adds the cost of each missing item to each quote so that every price covers the same scope.

Leveling three mechanical quotes to the same scope.
ItemMechanical AMechanical BMechanical C
Quoted price$1,795,000$1,850,000$1,768,000
Exhaust extraction connectionsExcluded: add $38,000IncludedExcluded: add $38,000
Building automation controlsExcluded: add $62,000IncludedIncluded
Fire stopping of mechanical penetrationsIncludedIncludedExcluded: add $12,000
Generator fuel pipingIncludedIncludedExcluded: add $24,000
Leveled price$1,895,000$1,850,000$1,842,000

After leveling, Mechanical C was $8,000 lower than Mechanical B. But C had not passed prequalification: its surety would not bond a contract of this size. Tamarack carried Mechanical B at $1,850,000. The lowest quoted price, Mechanical C at $1,768,000, would have looked attractive to a team that did not level, and would have left Tamarack with $74,000 of missing scope and an unbonded subcontractor on its largest package.

Owen's bid-day spreadsheet had one tab per package, each with a leveling table, the plug number Tamarack would use if no acceptable quote arrived, and a column for the subcontractor's acknowledgment of each addendum. A plug number is the contractor's own estimate of a package, used until real quotes arrive, and it is one of the reasons the earlier takeoff work matters.

Contingency and markups

With direct costs and general conditions in place, the estimate needed its top-of-the-page items. Each one is a business decision as much as a calculation, and Ruth made the final calls.

  • Pricing contingency of 2.5 % covered estimating uncertainty and minor risks that Tamarack carried under the contract. It was not meant for owner changes, which would be paid as changes.
  • Bonds and insurance of 1.6 % covered the performance and payment bonds, builder's risk insurance and the project share of liability insurance.
  • Fee of 5.5 % covered head office overhead and profit. Ruth set it after considering the expected competition and Tamarack's backlog.

Tomas turned the whole roll-up into a short program that the team reran every time a number changed on bid day. It printed the bid total and the share of direct cost in the five largest divisions, a quick check that nothing large had gone missing.

# Pembrook Fire Station No. 3: estimate roll-up from trade costs to bid price
trades = {
    '03 Concrete': 1_480_000, '04 Masonry': 620_000, '05 Metals': 1_150_000,
    '06 Wood and plastics': 210_000, '07 Thermal and moisture': 940_000,
    '08 Openings': 690_000, '09 Finishes': 780_000, '10 Specialties': 260_000,
    '11 Equipment': 340_000, '21 Fire suppression': 190_000, '22 Plumbing': 610_000,
    '23 HVAC': 1_240_000, '26 Electrical': 1_320_000, '27-28 Communications and alerting': 380_000,
    '31 Earthwork': 560_000, '32 Exterior improvements': 720_000, '33 Utilities': 410_000,
}
direct = sum(trades.values())
general_conditions = 14 * 48_000          # 14 months of site overhead
subtotal = direct + general_conditions
contingency = round(subtotal * 0.025)     # contractor's pricing contingency
before_bonds = subtotal + contingency
bonds_ins = round(before_bonds * 0.016)   # bonds and builder's risk/liability insurance
before_fee = before_bonds + bonds_ins
fee = round(before_fee * 0.055)           # head office overhead and profit
bid = before_fee + fee
for k, v in [('Direct trade cost', direct), ('General conditions', general_conditions),
             ('Pricing contingency 2.5%', contingency), ('Bonds and insurance 1.6%', bonds_ins),
             ('Fee 5.5%', fee), ('Bid price', bid)]:
    print(f'{k:26s} ${v:>12,}')
top = sorted(trades.items(), key=lambda kv: -kv[1])[:5]
print('Largest five trades:', ', '.join(k for k, _ in top), f'= {sum(v for _, v in top)/direct:.0%} of direct cost')
Output
Direct trade cost          $  11,900,000
General conditions         $     672,000
Pricing contingency 2.5%   $     314,300
Bonds and insurance 1.6%   $     206,181
Fee 5.5%                   $     720,086
Bid price                  $  13,812,567
Largest five trades: 03 Concrete, 26 Electrical, 23 HVAC, 05 Metals, 07 Thermal and moisture = 52% of direct cost
Waterfall chart building the bid price from direct trade cost through general conditions, pricing contingency, bonds and insurance and fee
How the bid price is built up from direct cost to the final total of $13,812,567.

The bid total of $13,812,567 worked out to about $727 per square foot of gross floor area. Tamarack's records for three recent municipal emergency services buildings, adjusted for location and escalation, ranged from $670 to $790 per square foot. The bid was also just under the town's published budget of about $14 million. Neither check proved the estimate right, but both suggested it was not badly wrong.

Alternates, unit prices and the bid form

The bid form asked for more than a single number. It required one separate price, for a rooftop solar array on the apparatus bay, and unit prices for rock excavation and for removing and replacing unsuitable soil. Owen priced the solar array at $186,000 from a specialty contractor's quote and the rock excavation unit price at $85 per cubic yard, which would be used if rock was found. The bid form also required the bidder to acknowledge each addendum by number, to attach the bid bond and the surety's agreement to provide contract bonds, and to list the major subcontractors.

Mistakes on the bid form, not in the estimate, are the most common reason a low bid is rejected. A missing addendum acknowledgment, an unsigned form, a bid bond in the wrong amount or a price written in words that does not match the figures can each disqualify a bid. Farah used a bid-form checklist and had a second person check every entry before Ruth signed. The envelope reached the town hall at 1:52.

Ethics on bid day

Bid day puts pressure on everyone, and some practices that look clever are unfair, unethical or illegal. Bid shopping is using one subcontractor's price to pressure another into a lower price after the bid, or shopping a price around before the bid in a way that breaks confidence. It damages trust and, in the long run, leads subcontractors to inflate their prices to the contractors who do it. Collusion between bidders, such as agreeing who will submit the low bid or sharing prices, is a serious crime in both Canada and the United States. Tamarack's policy was simple: keep every quote confidential, award to the subcontractor whose price was used when its bid was compliant, and never discuss prices with another general contractor.

At 3:15 the town posted the results. Tamarack was second of six, $41,000 above the low bidder, whose bid was later found to have omitted the generator. The town rejected the low bid as non-compliant and began its review of Tamarack's. For the capstone, the team continued as if Tamarack had been awarded the contract, with substantial completion due 14 months after award.

Your capstone deliverable

  • An estimate summary by division, with each line traced to quantities, productivity and rates, or to quotes.
  • A loaded labor rate build-up and productivity basis for self-performed work.
  • A general conditions estimate tied to the schedule duration.
  • A leveling table for at least two major subcontractor packages, with your reasons for the price carried.
  • Contingency and markups with your reasoning, the bid total and at least two benchmark checks.
  • A completed bid form, including separate prices, unit prices and addendum acknowledgments.

Common mistakes

  • MistakeUsing the lowest quoted price without leveling scope.

    InsteadAdd the cost of missing items to each quote so they cover the same scope.

  • MistakePricing labor at the base wage.

    InsteadUse loaded rates that include statutory costs, benefits and burden.

  • MistakeForgetting that general conditions depend on time.

    InsteadPrice them month by month from the schedule duration.

  • MistakeTreating contingency as profit or as a fund for owner changes.

    InsteadUse contingency for pricing risk the contractor carries; owner changes are paid as changes.

  • MistakeLosing a good bid to a form error.

    InsteadUse a bid-form checklist and a second check of every entry.

Summary and key terms

  • A stipulated price estimate has four layers: direct costs, general conditions, contingency and markups.
  • Self-performed work is priced from quantities, productivity and loaded labor rates.
  • General conditions are mostly time-related and should be built from the schedule.
  • Bid leveling adjusts subcontractor quotes to a common scope before comparison.
  • Prequalification can override price: an unbondable or unsafe low subcontractor is not a real saving.
  • Benchmarks per unit of floor area and against the owner's budget are useful checks, not proof.
  • Bid forms must be complete and correct; collusion and bid shopping are unethical, and collusion is illegal.
Direct cost
The cost of the work itself, from self-performed labor, material and equipment and subcontractor prices.
General conditions
Site costs that do not belong to one trade, such as supervision, the site office and temporary services.
Loaded labor rate
The hourly wage plus statutory costs, benefits and other employer costs.
Bid leveling
Adjusting subcontractor quotes to a common scope so they can be compared fairly.
Plug number
The contractor's own estimate of a package, used until acceptable quotes arrive.
Unit price
A price per unit of work, used to adjust the contract if quantities change.

Practice problems

Work each problem on paper first, then reveal the answer to check.

  1. A wage is $38.00 per hour, payroll taxes and insurance are 22 % and fringes are $10.20 per hour. What is the loaded rate?

    Show answer

    $38.00 + $8.36 + $10.20 = $56.56 per hour.

  2. Quote X is $900,000 and excludes $45,000 of scope. Quote Y is $930,000 and is complete. Which is lower after leveling?

    Show answer

    X levels to $945,000, so Y at $930,000 is lower.

  3. Why are general conditions priced from the schedule?

    Show answer

    Most of them, such as supervision and site facilities, cost a fixed amount per month.

  4. A bid of $9,450,000 is for a building of 13,500 ft². What is the cost per square foot?

    Show answer

    $9,450,000 ÷ 13,500 = $700 per ft².

  5. Give three bid-form errors that can disqualify a bid.

    Show answer

    Any three of: missing addendum acknowledgment, unsigned form, wrong bid bond amount, words and figures that disagree, late delivery.

Lesson quiz · 5 questions

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