Commercial construction NAICS codes fall into three federal subsectors: 236 for building construction, 238 for specialty trades, and 237 for heavy and civil engineering. The six-digit code you carry decides your SBA small business status, shapes which federal contracts you show up for, and sets the principal business activity line on your tax return. Pick the wrong one and you can lose contract opportunities or, if the misstatement affects size status, face federal penalties.
Codes for General Commercial Builders
If your firm acts as the general contractor on a commercial project, you almost certainly sit in the 236 subsector. Two codes do most of the work, and the line between them trips people up.
236220 — Commercial and Institutional Building Construction is the workhorse code for commercial GCs. It covers office buildings, retail centers, schools, hospitals, clinics, warehouses, and similar nonresidential structures.1NAICS Association. 236220 – Commercial and Institutional Building Construction The detail that catches contractors: warehouses live here, not under the industrial code. Census classifies them as commercial buildings.
236210 — Industrial Building Construction is narrower than the name suggests. It covers manufacturing plants, assembly facilities, cement plants, and other structures built to house production processes. Warehouses, power generation plants, and water treatment plants are excluded.2U.S. Bureau of Labor Statistics. May 2023 National Industry-Specific Occupational Employment and Wage Estimates Storage buildings belong in 236220 even when they look industrial.
One boundary worth flagging: high-rise apartments and condominiums feel commercial in scale but carry a residential code. NAICS 236116 covers new multifamily housing, including high-rise buildings where units share walls. A firm building both apartment towers and offices has to decide which activity brings in more revenue, because residential and commercial codes can carry different SBA size thresholds.
Codes for Specialty Trade Subcontractors
If your firm handles a specific trade rather than managing the whole project, you belong in the 238 subsector regardless of the size of the job you’re on.3U.S. Bureau of Labor Statistics. Specialty Trade Contractors: NAICS 238 The codes that come up most on commercial sites:
- 238110 — Poured Concrete Foundation and Structure Contractors. Foundations, slabs, retaining walls, and structural frameworks.4U.S. Census Bureau. North American Industry Classification System – 238910
- 238210 — Electrical Contractors and Other Wiring Installation Contractors. Wiring, lighting, and communication equipment installation.5U.S. Bureau of Labor Statistics. NAICS 238210 – Electrical Contractors and Other Wiring Installation Contractors
- 238220 — Plumbing, Heating, and Air-Conditioning Contractors. Plumbing, HVAC, and mechanical systems, parts and labor.6U.S. Census Bureau. 2022 NAICS Definition – 238220 Plumbing, Heating, and Air-Conditioning Contractors
- 238160 — Roofing Contractors. Commercial roof installation, including membrane systems, sheet metal, and waterproofing. Firms that mainly install gutters and soffits fall under 238170 (Siding Contractors).
- 238910 — Site Preparation Contractors. Excavation, grading, demolition, land clearing, earth moving for nonbuilding sites, and construction equipment rental with an operator.
Other codes commonly seen on commercial jobs include 238120 (structural steel and precast concrete), 238130 (framing), 238310 (drywall and insulation), and 238320 (painting). The full specialty list runs to roughly 20 codes, each tied to a distinct trade.
Codes for Site Infrastructure and Civil Work
Some commercial projects involve work outside the building itself, and that work sits in the 237 subsector. Key codes are 237100 (utility system construction), 237310 (highway, street, and bridge construction), and 237210 (land subdivision). Most commercial contractors won’t carry a 237 code as their primary, but if your firm’s main revenue comes from utility connections, road access, or subdivision work rather than the buildings themselves, you belong here rather than in 236 or 238.
How to Choose When Your Firm Does More Than One Thing
Census classifies businesses by similarity of production processes, not just by what the finished project looks like.7United States Census Bureau. Economic Census – NAICS Codes and Understanding Industry Classification Systems For a firm with mixed activities, that means identifying which activity generates the largest share of revenue. A company earning 60% from electrical contracting and 40% from general building management belongs in 238210, not 236220.
The IRS applies the same idea on Schedule C, telling filers to select the six-digit code that best identifies “the principal source of your sales or receipts.”8Internal Revenue Service. 2025 Instructions for Schedule C (Form 1040) The IRS uses a condensed list, so some codes get grouped. Nonresidential building construction, for example, appears on the IRS list as 236200 rather than split into 236210 and 236220. When your exact code isn’t on the IRS list, use the closest available match.
Verify against the official descriptions on the Census NAICS site, which spells out what each code includes and excludes.9U.S. Census Bureau. North American Industry Classification System Read the exclusion lists carefully. Most misclassifications come from assumptions about where a code stops, and the warehouse case sits right at that boundary.
Why the Code Matters for Federal Contracts
Your NAICS code determines whether you qualify as a small business for federal contracting. The SBA attaches a size standard to each code, expressed as maximum average annual receipts. Construction size standards currently sit roughly between $19 million and $45 million, though the SBA adjusts these periodically for inflation.10U.S. Small Business Administration. Table of Size Standards Check the current table before relying on a specific figure.
When you register in SAM.gov, the codes you list are what contracting officers use to find qualified bidders.11U.S. Small Business Administration. Basic Requirements A wrong code means you either miss searches for work you can do or surface for work you can’t.
Misrepresenting small business size status carries serious consequences. Under 15 U.S.C. § 645, knowingly claiming small business status when your firm exceeds the size standard can bring a fine of up to $500,000, imprisonment for up to 10 years, or both.12Office of the Law Revision Counsel. 15 USC 645 – Offenses and Penalties Administrative consequences like debarment can follow even without intent to defraud.
How the Code Affects Insurance Premiums
Insurance carriers use NAICS codes as a starting point for risk. A firm classified under 238110 (poured concrete) will typically see higher workers’ compensation premiums than one classified under 236220, because hands-on trade work carries more injury risk. Your experience modification rate and claims history matter too, but a misaligned code can leave you either overpaying or facing a premium audit adjustment that lands all at once when the carrier catches the mismatch.
The 2027 NAICS Revision
NAICS is updated roughly every five years through a joint process involving the United States, Canada, and Mexico. The next revision targets a January 2027 release, with an OMB final decision on changes due by March 2026 and the updated manual online in early 2027.13United States Census Bureau. NAICS Update Process Fact Sheet No construction-specific changes have been publicly finalized as of early 2026. If your firm currently sits awkwardly inside a broader code, watch the 2027 cycle for a possible better fit.