Pricing Materials: Unit Costs, Supplier Quotes, and the Estimate Summary

Pricing Materials: Unit Costs, Supplier Quotes, and the Estimate Summary

Why Pricing Matters

A bill of materials (BOM) tells you what you need and how much. Pricing converts those quantities into dollars. An accurate estimate protects the contractor from losing money on a job and gives the owner a realistic budget. One math error carried through a spreadsheet can cost thousands of dollars, so every number must be checked before the estimate leaves your hands.

Reading a Supplier Quote or Price Sheet

Before you multiply anything, read the price sheet carefully. Four pieces of information govern every line:

Unit of measure (UOM). Lumber is priced per linear foot or per board foot; drywall by the sheet; concrete by the cubic yard; roofing materials by the square (100 sq ft). If your quantity is in square feet and the price is per square, you must convert before you multiply.

Price breaks. Many suppliers offer lower unit prices at higher quantities—for example, a different rate per sheet for orders over 50 sheets versus under 50. Always check which tier your quantity falls into.

Delivery charges. Delivery may be a flat fee, a per-mile rate, or free above a minimum order. Record it as a separate line item; do not hide it inside unit costs.

Sales tax. Most states tax construction materials. Tax is applied to the material subtotal after all line items are summed, not to each line individually. Confirm your state and local rate with your instructor; never guess.

The Pricing Formula

Every line on a priced BOM uses one formula:

> Quantity × Unit Cost = Extended Cost

In a spreadsheet, if quantity is in column C and unit cost is in column D, the formula in column E is `=C2*D2`. Copy that formula down every row. Never type an extended cost by hand—a formula catches a keying error; a hand-typed number hides it.

Material Cost vs. Installed Cost

A material cost covers only what you buy from the supplier. An installed cost (also called the all-in cost) adds labor, equipment, and overhead to place that material in the building. This course focuses on material cost, but you need to know the difference because an owner may ask why your estimate is lower than a contractor's bid—the bid includes installed cost.

CSI MasterFormat Divisions

The Construction Specifications Institute (CSI) MasterFormat organizes construction work into numbered divisions so that everyone on a project uses the same language. For this program you will use five divisions:

• Division 03 – Concrete: footings, slabs, cast-in-place walls
• Division 04 – Masonry: concrete masonry units (CMU), brick
• Division 06 – Wood, Plastics, and Composites: dimensional lumber, engineered wood, rough framing
• Division 07 – Thermal and Moisture Protection: insulation, roofing, waterproofing, house wrap
• Division 09 – Finishes: drywall, joint compound, tape, paint, flooring

Assigning each material to the correct division keeps the estimate organized and makes it easy for an owner, architect, or lender to review specific portions of the work.

Building the Estimate Summary

The estimate summary combines all priced BOMs into one document. Follow these steps:

1. Collect priced BOMs from each previous lesson (concrete, masonry, framing, roofing/thermal, finishes).

2. Group line items by CSI division. Each division becomes a section of the summary.

3. Subtotal each division. Sum the extended costs within each section.

4. Add delivery charges as a separate line below all divisions, or within the division they serve.

5. Calculate the material subtotal (sum of all division subtotals plus delivery).

6. Apply sales tax to the material subtotal.

7. State the grand total.

Label every column clearly: Description, UOM, Quantity, Unit Cost, Extended Cost. Include the project name, date, preparer's name, and a note that the estimate covers materials only.

The Summary Memo

Attach a two-paragraph memo to the printed estimate. The first paragraph identifies the project, the scope covered, and the date. The second paragraph highlights any assumptions (e.g., prices are based on quotes valid for 30 days, tax rate assumed, delivery included or excluded). A clear memo prevents misunderstandings and demonstrates professionalism.

Accuracy and Safety

Arithmetic errors in an estimate are not a safety issue in the physical sense, but they create financial harm. Treat formula checking the way you treat lockout/tagout on a job site—it is a required step, not optional. Before printing:

• Verify every formula by spot-checking three or more lines with a calculator.
• Confirm that UOM conversions are correct on every line.
• Confirm the tax rate is applied only once, to the subtotal.
• Have a second person review the grand total.

When working in the computer lab, follow the lab's electrical safety rules: do not bring liquids near equipment, and report any frayed cords or damaged outlets to the instructor immediately.