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Tax Preparation Hints - Construction Tax Tips

When completing your tax return, it is important to properly classify your business that provided your principal source of income. These codes for the Principal Business or Professional Activity classify sole proprietorships by the type of activity they are engaged in to facilitate the administration of the Internal Revenue Code. These six-digit codes are based on the North American Industry Classification System (NAICS).

Line A of Form 1040 Schedules C and C-EZ requires a Principal Business or Professional Activity  description to be entered. Select the category that best describes your primary business activity within the construction industry (refer to the table below). If you owned more than one business, you must complete a separate Schedule C or Schedule C-EZ for each business.

Line B of Form 1040 Schedules C and C-EZ also requires a Principal Business or Professional Activity description to be entered. However, this code should represent the activity that best identifies the principal source of your sales or receipts (i.e. your principal customers or clients). Refer to the table of codes listed below or Instructions for Schedule C, (PDF) Profit or Loss From Business.

Professional Business or Professional Activity Codes for the Construction Industry

Construction of Buildings



Nonresidential building construction


Residential building construction

Heavy and Civil Engineering Construction



Highway, street, & bridge construction

237210 Land subdivision
237100 Utility system construction


Other heavy & civil engineering construction

Special Trade Contractors



Drywall & insulation contractors


Electrical contractors


Finish carpentry contractors


Flooring contractors


Glass & glazing contractors


Masonry contractors


Painting & wall covering contractors


Plumbing, heating & air-conditioning contractors


Poured concrete foundation & structure contractors

238160 Roofing contractors
238170 Siding contractors
238910 Site preparation contractors
238120 Structural steel & precast concrete construction contractors
238340 Tile & terrazzo contractors
238290 Other building equipment contractors
238390 Other building finishing contractors
238190 Other foundation, structure, & building exterior contractors


All other specialty trade contractors

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Page Last Reviewed or Updated: 05-Oct-2015