11.1 Construction Estimating

Why Estimating Matters on the MHIC Exam

The contractor examination administered by PSI for the Maryland Home Improvement Commission (MHIC) includes a dedicated estimating content area — three scored items on the official content outline. Estimating questions are less about memorizing prices and more about method: can you convert drawings and a scope of work into quantities, convert quantities into costs, and convert costs into a selling price that covers overhead and still leaves a profit. A contractor who estimates poorly either loses money on every job or loses every bid to competitors, so the exam treats estimating as a core business survival skill.

The Quantity Takeoff

Every estimate begins with a quantity takeoff: a systematic measurement of every work item shown on the plans or described in the scope. Takeoff units must match the way work is actually bought and installed — square feet for roofing, flooring, drywall, and paint; linear feet for baseboard, fencing, and trim; cubic yards for concrete and excavation; and each for fixtures, windows, and doors.

Worked example — a concrete patio slab measuring 30 feet by 20 feet and 4 inches thick:

• Area: 30 ft × 20 ft = 600 square feet
• Volume: 30 ft × 20 ft × (4 in ÷ 12 in/ft) = 200 cubic feet
• Convert to cubic yards: 200 ÷ 27 = 7.41 cubic yards
• With waste and spillage, order roughly 8 cubic yards

The conversion of 27 cubic feet per cubic yard is a classic exam calculation — memorize it.

Unit Costs and the Cost Breakdown

A unit cost is the total installed cost of one unit of work — for example, $14 per square foot of installed ceramic tile. Building a unit cost means adding its three components:

Do not forget labor burden — the payroll taxes and insurance paid on top of base wages, often adding 25 to 40 percent to the hourly rate. An estimate built on bare wages is an estimate built to lose money.

Overhead Versus Profit

Direct costs (also called job costs) are expenses traceable to a specific project: the crew's wages on that job, materials delivered to that address, equipment rented for that work, and subcontractor invoices. Overhead (indirect cost) is everything it takes to keep the company alive whether or not a particular job exists — office rent, the estimator's salary, liability insurance premiums, vehicles, phones, advertising, and licensing fees. Profit is what remains after the job pays its direct costs and its fair share of overhead. A bid that covers only direct costs is priced to break even at best.

Overhead is recovered by building it into the price as a percentage of job costs or as a daily or weekly rate. If annual overhead is $120,000 and the company sells $600,000 of work a year, overhead consumes 20 percent of every dollar billed and must be recovered in every price.

Markup Versus Margin — the Classic Exam Trap

Markup is a percentage of cost. Margin (gross margin) is a percentage of the selling price. The same dollar profit produces different percentages under each method, and exam writers exploit the confusion.

Worked example — a job costs $10,000:

• 20% markup: price = $10,000 × 1.20 = $12,000. Profit is $2,000, and the margin is $2,000 ÷ $12,000 = only 16.7%.
• 20% margin: the cost must equal 80% of the price, so price = $10,000 ÷ (1 − 0.20) = $12,500. Profit is $2,500.

Same label — 20 percent — but a $500 difference in the price. The safe formulas: to hit a target margin, divide cost by (1 − margin); to apply a markup, multiply cost by (1 + markup).

Allowances and Contingencies

An allowance is a budget placeholder for an item the homeowner has not yet selected — for example, a $3,000 allowance for kitchen cabinetry. The contract reconciles the allowance later: the homeowner pays more if the actual selection exceeds it and receives a credit if it comes in under. Allowances keep a bid moving when selections lag, but unrealistically low allowances are a leading cause of homeowner disputes — and disputes are exactly what MHIC investigators see.

A contingency is a reserve for unknown conditions — rotted sheathing behind siding, unmarked utilities, code-required upgrades discovered mid-job. Residential remodelers commonly carry 5 to 10 percent contingency on renovation work, where hidden conditions are routine.

Bid Accuracy and Scope Gaps

Before submitting, review the estimate for the two classic failures. A scope gap is work nobody priced — the electrician assumed the drywall crew patches around the new panel, and the drywaller assumed the electrician did. A scope overlap is work priced twice, inflating the bid and losing the job. Defenses include a written scope checklist tied to the takeoff, explicit exclusions listed in the proposal (permits, painting, landscaping repair), a second person reviewing the bid summary, and unit-cost sanity checks against recent completed jobs. Rushed bids at deadline are where arithmetic errors and scope gaps slip through — build in time for the final review.