NASCLA Commercial Exam Study Guide (2026)
Everything the NASCLA Commercial General Building Exam tests, topic by topic: what each section covers, the facts that come up most, and how to study it. Pair it with the free 15-question practice test.
The exam at a glance
| Questions | 115 scored + 10 unscored pretest |
|---|---|
| Time | 5 hours 30 minutes (330 min) |
| Passing score | 70% (81 of 115 correct) |
| Format | Open book (approved references, tabbed and highlighted only) |
| Licensing body | NASCLA (National Association of State Contractors Licensing Agencies) |
| Test provider | PSI |
Mind map: the whole exam on one screen
1. Business, Contracts and Payroll
This topic covers running a contracting business: payroll taxes, hiring paperwork, bonds, contract clauses and basic financial ratios. Questions are often short calculations or definitions you can look up in the business reference, so speed matters.
Key facts
- FUTA tax is 6.0% on the first $7,000 of each employee's annual wages (IRC §3301, §3306).
- For 2026, Social Security tax is 6.2% each for employer and employee on wages up to $184,500. Medicare is 1.45% each with no wage cap (SSA, IRC §3101, §3111).
- The employer must complete Section 2 of Form I-9 within 3 business days of the employee's first day of paid work (8 CFR 274a.2).
- Keep each Form I-9 for 3 years after the hire date or 1 year after employment ends, whichever is later (8 CFR 274a.2).
- Non-exempt employees earn overtime at 1.5 times the regular rate for hours over 40 in a workweek (FLSA, 29 U.S.C. §207).
- Current ratio = current assets / current liabilities. Working capital = current assets minus current liabilities.
- A performance bond protects the owner if the contractor fails to finish. A payment bond protects subcontractors and suppliers. A bid bond backs the bidder's promise to sign the contract.
Flashcards
Exam tip: On markup and margin questions, check which base the question uses: a 20% markup on cost is only a 16.7% margin on price.
2. Safety (OSHA 1926)
Safety questions come straight from 29 CFR Part 1926, the federal construction safety standards. Most ask for a specific trigger height, distance or load, so a well-tabbed copy of the CFR is your best tool.
Key facts
- Fall protection is required at 6 feet or more above a lower level on walking/working surfaces with an unprotected side or edge (29 CFR 1926.501(b)(1)).
- Guardrail top rails must be 42 inches plus or minus 3 inches high and withstand 200 pounds applied outward or downward (29 CFR 1926.502(b)).
- Personal fall arrest anchorages must support 5,000 pounds per employee attached, or be designed by a qualified person with a safety factor of at least two (29 CFR 1926.502(d)(15)).
- Scaffolds must support their own weight plus at least 4 times the maximum intended load. Fall protection is required on scaffolds more than 10 feet above a lower level (29 CFR 1926.451(a)(1), (g)(1)).
- Extension ladders must extend at least 3 feet above the upper landing and be set at a 4 to 1 ratio (base 1 foot out for every 4 feet of working length) (29 CFR 1926.1053(b)).
- A stairway or ladder is required at personnel access points with a break in elevation of 19 inches or more (29 CFR 1926.1051(a)).
- Provide one fire extinguisher rated at least 2A for each 3,000 square feet, with no more than 100 feet of travel to reach one (29 CFR 1926.150(c)(1)(i)).
Flashcards
Exam tip: Do not mix up the general 6-foot rule with the special heights for scaffolds (10 feet) and steel erection (15 feet).
3. Site Work and Excavation
This topic covers trenching and excavation safety, soil classification, sloping and earthwork basics. Most numbers come from OSHA Subpart P (29 CFR 1926.650 to 1926.652) and its appendices.
Key facts
- A protective system (sloping, benching, shoring or shielding) is required in excavations 5 feet or deeper unless made entirely in stable rock (29 CFR 1926.652(a)(1)).
- Protective systems for excavations deeper than 20 feet must be designed by a registered professional engineer (29 CFR 1926.652(b), (c)).
- Keep spoil and equipment at least 2 feet from the excavation edge (29 CFR 1926.651(j)(2)).
- Trenches 4 feet or deeper need a ladder, stairway or ramp within 25 feet of lateral travel for workers (29 CFR 1926.651(c)(2)).
- Maximum allowable slopes: Type A soil 3/4:1, Type B 1:1, Type C 1-1/2:1 (horizontal to vertical) (29 CFR 1926 Subpart P, Appendix B).
- Type A soil has an unconfined compressive strength of 1.5 tons per square foot or more. Type C is 0.5 tsf or less (29 CFR 1926 Subpart P, Appendix A).
- A competent person must inspect excavations daily before work starts and after rain or other hazard-increasing events (29 CFR 1926.651(k)(1)).
Flashcards
Exam tip: Read whether the question asks about 4 feet (egress and air testing) or 5 feet (protective systems); both numbers appear in Subpart P.
Test yourself on these topics
Take the free 15-question NASCLA Commercial test, then save your results to unlock your Readiness Score and the mistakes bank.
4. Concrete and Reinforcing Steel
Expect questions on concrete testing, mix properties, rebar sizes and weights, and minimum cover over reinforcement. Values come from ACI 318, ASTM standards and OSHA Subpart Q.
Key facts
- Specified compressive strength (f'c) is normally based on 28-day cylinder tests.
- The slump test measures consistency (workability) of fresh concrete, not strength (ASTM C143).
Flashcards
Exam tip: For cover questions, first decide the exposure (cast against earth, exposed to weather, or interior), then the bar size.
5. Masonry
Masonry questions cover mortar types, unit sizes, grout, cold weather rules and wall bracing safety. Many are lookups in TMS 602, ASTM C270 or OSHA Subpart Q.
Key facts
- Minimum mortar compressive strengths: Type M 2,500 psi, Type S 1,800 psi, Type N 750 psi, Type O 350 psi (ASTM C270).
- A nominal 8 x 8 x 16 CMU is actually 7-5/8 x 7-5/8 x 15-5/8 inches; the 3/8-inch mortar joint makes up the difference.
Flashcards
Exam tip: Remember the mortar order with the word MaSoNwOrk: M, S, N, O from strongest to weakest.
6. Metals and Wood Framing
This topic covers structural steel shapes, steel erection safety, lumber sizes and framing takeoffs. Expect a mix of definitions and quick math like board feet and stud counts.
Key facts
- In W12 x 26, W is a wide-flange shape, 12 is the nominal depth in inches and 26 is the weight in pounds per foot.
- All columns must be anchored by at least 4 anchor rods (29 CFR 1926.755(a)(1)).
Flashcards
Exam tip: Board foot math always uses nominal sizes, not actual dressed sizes.
7. Thermal, Moisture, Doors, Windows
This topic covers roofing, insulation, vapor control, door sizes and safety glazing. Many questions come from the International Building Code and basic building science.
Key facts
- One roofing square equals 100 square feet of roof surface.
- Asphalt shingles require a slope of at least 2:12. Slopes from 2:12 up to 4:12 require double underlayment (IBC 1507.2.2).
Flashcards
Exam tip: Roof area for squares is the sloped surface area, so on pitched roofs do not just use the floor plan footprint.
8. Finishes and Specialties
This topic covers gypsum board, paint and floor finishes, and specialty items like toilet accessories and accessibility features. Expect material definitions and simple coverage math.
Key facts
- Type X gypsum board has a special core for improved fire resistance and is used in fire-rated assemblies (ASTM C1396).
- A standard 4 x 8 gypsum sheet covers 32 square feet; a 4 x 12 sheet covers 48 square feet.
Flashcards
Exam tip: On material quantity questions, always round up to whole units you can actually buy.
9. Plan Reading, Estimating, Scheduling
This topic tests reading drawings at scale, calculating quantities and understanding CPM schedules. It is math-heavy, so practice the core conversions until they are automatic.
Key facts
- 1 cubic yard = 27 cubic feet. Cubic yards = length (ft) x width (ft) x depth (ft) / 27.
- A 30 x 40 ft slab, 4 inches thick, needs 400 cubic feet, or 14.81 cubic yards, before waste.
Flashcards
Exam tip: Convert every dimension to feet before multiplying, especially slab thickness in inches, then divide by 27 for cubic yards.
How to pass
- It's open book, so speed of lookup matters more than memorizing. Tab your references by chapter before test day.
- 81 correct passes. Answer every question; there is no penalty for guessing.
- Budget about 2.5 minutes per question and flag long estimating problems for the end.
- Passing NASCLA covers the trade portion only. You still take each state's own Business & Law exam.
Frequently asked questions
How long should I study for the NASCLA Commercial exam?
Most working candidates need 4 to 8 weeks at 45 to 60 minutes a day. Book your exam once your Readiness Score has stayed at 80 or higher for about a week.
Is the NASCLA Commercial exam open book?
Open book (approved references, tabbed and highlighted only). Check the current candidate information bulletin from NASCLA (National Association of State Contractors Licensing Agencies) for the approved reference list and tabbing rules.
What score do I need to pass the NASCLA Commercial exam?
70% (81 of 115 correct). The exam has 115 scored + 10 unscored pretest and a time limit of 5 hours 30 minutes (330 min).
What are the most tested topics?
The outline covers business, contracts and payroll, safety (osha 1926), site work and excavation, concrete and reinforcing steel, masonry, metals and wood framing, thermal, moisture, doors, windows, finishes and specialties, plan reading, estimating, scheduling. Use the free practice test to see which ones you need most.
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Summarized from official candidate information and the statutes, codes and regulations cited, checked October 2026. Confirm current requirements with NASCLA (National Association of State Contractors Licensing Agencies).