> Enrich.chat gives AI agents verified work emails and mobiles. To use it from an agent, read https://enrich.chat/agents.md . This is the Markdown version of https://enrich.chat/naics/236220/illinois/ # NAICS 236220 companies in Illinois Companies with NAICS code 236220 (Commercial and Institutional Building Construction) headquartered in Illinois, with their cities, sizes and SIC codes. By Enrich.chat Editorial. Updated October 22, 2026. **Short answer:** The biggest NAICS 236220 companies in Illinois by headcount range include Clayco, Pepper Construction Group and Graycor. NAICS 236220 is the code for Commercial and Institutional Building Construction. Among those counted, they are mostly very small: 63% have 50 or fewer employees. ## Which NAICS 236220 companies are in Illinois? The biggest by headcount range include Clayco, Pepper Construction Group, Graycor, Power Construction and F.H. Paschen. NAICS 236220 is the code for Commercial and Institutional Building Construction. Names link to a company profile where we have one. | Company | City | Employees | | --- | --- | --- | | Clayco | Chicago | 1,001 to 5,000 | | Pepper Construction Group | Chicago | 501 to 1,000 | | Graycor | Oakbrook Terrace | 501 to 1,000 | | Power Construction | Chicago | 201 to 500 | | F.H. Paschen | Chicago | 201 to 500 | | Mcshane Construction | Rosemont | 201 to 500 | | Bear Construction | Rolling Meadows | 201 to 500 | | Fcl Builders | Itasca | 201 to 500 | | Berglund Construction | Chicago | 201 to 500 | | Krusinski Construction | Oak Brook | 51 to 200 | | Holland Construction Services | Swansea | 51 to 200 | | Poettker Construction | Breese | 51 to 200 | | Nicholas & Associates | Mount Prospect | 51 to 200 | | Norcon | Chicago | 51 to 200 | | Peak Construction | Rosemont | 51 to 200 | | Pointcore Construction | Peoria | 51 to 200 | | Helmkamp Construction | East Alton | 51 to 200 | | Burling Builders | Chicago | 51 to 200 | | Henry Bros. | Hickory Hills | 51 to 200 | | Phoenix Builders | Elgin | 51 to 200 | | Mark 1 Restoration | Dolton | 51 to 200 | | Omni Commercial Group | Elgin | 51 to 200 | | G.S. Floor Designs | Arlington Heights | 51 to 200 | | Cpmh Construction | Chicago | 51 to 200 | | Meridian Design Build | Rosemont | 11 to 50 | The table shows the 25 biggest by headcount range, with ties broken by audience size. The charts and percentages below cover every company counted for this page, not just these 25, and companies with fewer than 11 employees are not counted. Headquarters is the location on each company's public profile. ## How big are they? 63% of the NAICS 236220 companies counted in Illinois have 50 or fewer employees, and the middle one is in the 11 to 50 range. Companies with fewer than 11 employees are not counted. **Figure: Size of NAICS 236220 companies in Illinois.** Seven columns for the share of counted NAICS 236220 companies in Illinois in each employee range: 11 to 50 63%, 51 to 200 23%, 201 to 500 9%, 501 to 1,000 3%, 1,001 to 5,000 2%, 5,001 to 10,000 0%, 10,001+ 0%. *Share of counted NAICS 236220 companies in Illinois in each employee range.* ## Which SIC codes do they carry? The older SIC system and NAICS do not line up one to one. These are the SIC codes seen most here. **Figure: SIC codes of NAICS 236220 companies in Illinois.** Bars for the share of counted NAICS 236220 companies in Illinois with each code: 1542 72%, 1541 15%, 1521 5%, 1522 5%. *Share of counted NAICS 236220 companies in Illinois by their SIC code.* [SIC 1541](https://enrich.chat/sic/1541/) ## How do you reach the people at these Illinois companies? The people to talk to are usually owners, operations and procurement leaders. Build the list in three prompts to your AI agent. ### 1. Count them (free) Counting who matches never uses credits. ```text Use www.enrich.chat to count the companies with NAICS code 236220 in Illinois ``` ### 2. Find the people (5 credits per person) Name the roles you sell to. Each person returned is 5 credits, and name, title and company are included. ```text Use www.enrich.chat to find the owners, operations and procurement leaders at companies with NAICS code 236220 in Illinois, with their titles ``` ### 3. Get their work emails (10 credits each) An email is 10 credits only when one is found. Every email comes with a status: verified, catch-all or unknown. ```text Use www.enrich.chat to find the work emails for these people and tell me which ones are verified ``` ## More to explore About the code: [NAICS 236220: Commercial and Institutional Building Construction](https://enrich.chat/naics/236220/). About the place: [companies in Illinois](https://enrich.chat/companies-in/illinois/). NAICS 236220 in other states: [California](https://enrich.chat/naics/236220/california/)[Texas](https://enrich.chat/naics/236220/texas/)[Florida](https://enrich.chat/naics/236220/florida/)[New York](https://enrich.chat/naics/236220/new-york/)[Pennsylvania](https://enrich.chat/naics/236220/pennsylvania/)[Washington](https://enrich.chat/naics/236220/washington/)[North Carolina](https://enrich.chat/naics/236220/north-carolina/)[Virginia](https://enrich.chat/naics/236220/virginia/)[Georgia](https://enrich.chat/naics/236220/georgia/)[Ohio](https://enrich.chat/naics/236220/ohio/) Other NAICS codes in Illinois: [NAICS 541511: Custom Computer Programming Services](https://enrich.chat/naics/541511/illinois/)[NAICS 541512: Computer Systems Design Services](https://enrich.chat/naics/541512/illinois/)[NAICS 722511: Full-Service Restaurants](https://enrich.chat/naics/722511/illinois/)[NAICS 531210: Offices of Real Estate Agents](https://enrich.chat/naics/531210/illinois/)[NAICS 524210: Insurance Agencies and Brokerages](https://enrich.chat/naics/524210/illinois/)[NAICS 541613: Marketing Consulting Services](https://enrich.chat/naics/541613/illinois/)[NAICS 621111: Offices of Physicians](https://enrich.chat/naics/621111/illinois/)[NAICS 488510: Freight Transportation Arrangement](https://enrich.chat/naics/488510/illinois/)[NAICS 238220: Plumbing, Heating, and Air-Conditioning](https://enrich.chat/naics/238220/illinois/)[NAICS 621999: All Other Miscellaneous Ambulatory](https://enrich.chat/naics/621999/illinois/) ## Frequently asked questions ### Which NAICS 236220 companies are in Illinois? The biggest by headcount range include Clayco, Pepper Construction Group, Graycor, Power Construction and F.H. Paschen. The page lists 25 with links to their profiles where we have them. ### What is NAICS 236220? NAICS 236220 is the code for Commercial and Institutional Building Construction, in sector 23: Construction. ### Which cities in Illinois have the most? Chicago (29%), Northbrook (5%) and Rosemont (5%) lead among the companies counted. ## Try this prompt Find the people at NAICS 236220 companies in Illinois ```text Use www.enrich.chat to find the owners, operations and procurement leaders at companies with NAICS code 236220 in Illinois, with titles and verified work emails ``` ## Related - [Companies using a technology](https://enrich.chat/companies-using/) - [NAICS 236220 in California](https://enrich.chat/naics/236220/california/) - [NAICS 236220 in Texas](https://enrich.chat/naics/236220/texas/) - [NAICS 236220 in Florida](https://enrich.chat/naics/236220/florida/) - [NAICS 236220 in New York](https://enrich.chat/naics/236220/new-york/) - [NAICS 541511 in Illinois](https://enrich.chat/naics/541511/illinois/) - [NAICS 541512 in Illinois](https://enrich.chat/naics/541512/illinois/) - [NAICS 722511 in Illinois](https://enrich.chat/naics/722511/illinois/) - [NAICS 531210 in Illinois](https://enrich.chat/naics/531210/illinois/) - [Tech stack lookup](https://enrich.chat/tools/tech-stack-lookup/)