Illinois (IDFPR) Engineering Guide: Mandatory Structural Engineer (SE) Licence, Chicago Plan Review and Midwest CAD and Staffing Rates

01Two licences, two acts: PE and SE in Illinois

Engineering in Illinois is regulated by the Illinois Department of Financial and Professional Regulation (IDFPR), advised by separate boards for professional engineers and structural engineers. There are two statutes, and the split between them is the point of this page:

• The Professional Engineering Practice Act of 1989 governs PEs: civil, mechanical, electrical and other disciplines.
• The Structural Engineering Licensing Act of 1989 governs SEs, and reserves the practice of structural engineering, as the Act defines it, to licensed Structural Engineers.

In most states a civil PE who is competent in structures can seal a building's structural design. In Illinois that generally does not work. The structural design of buildings and other structures within the Act's definition needs an Illinois SE, who has passed the NCEES 16-hour SE exam and met the Illinois experience requirements. The Act has narrow exemptions; check IDFPR's current rule before relying on one.

The effect for buyers: the eligible pool is small, out-of-state firms often lack an Illinois SE, and fees run higher than in neighboring states. Mechanical, electrical and civil site work stay with PEs in the usual way.

02Design firm registration and licensing from out of state

Illinois requires a business entity that offers engineering to register as a professional design firm with IDFPR, naming a managing agent who holds the relevant Illinois licence. A firm offering structural engineering needs an Illinois SE in that role for the structural work. Registration is renewed on IDFPR's cycle; check the current fee and renewal date.

For an engineer licensed elsewhere, Illinois licenses by endorsement, typically through the NCEES Record. For an SE, the important question is the exam: Illinois expects the 16-hour SE exam. An engineer who passed only the PE Civil Structural exam generally cannot be endorsed as an Illinois SE. Check IDFPR's current rule for older exam histories.

Our benchmark for adding Illinois to an engineer's and firm's portfolio is $425 ($225 individual application plus $200 firm registration average). The fee is small; the eligibility test is not.

What to ask an out-of-state structural subconsultant before award:

1. Does a named engineer hold an active Illinois SE licence, not only an Illinois PE?
2. Is the firm registered as an Illinois professional design firm with that SE as managing agent for structural work?
3. If not, which Illinois SE will be engineer of record, and will that SE have genuine responsible charge, with their own checks and file, rather than reviewing at the end?

A common compliant model is an Illinois SE firm as engineer of record with the out-of-state team producing models and drawings under that SE's direction. Price that in from the start.

03Chicago plan review and self-certification

Chicago runs its own building department and its own building code, based on the International Building Code with Chicago amendments. For buyers, three review routes matter:

• Standard plan review, where the Department of Buildings reviews each discipline. Expect comment rounds; most engineering quotes include one response round and bill the rest hourly.
• Self-certification, where a qualifying architect or engineer who has completed the city's program certifies code compliance and the permit issues faster, subject to audit. Ask your engineer whether they are enrolled and their audit record.
• Developer services for large or complex projects, with coordinated review.

Outside Chicago, suburban municipalities often use third-party plan reviewers. Turnaround is usually faster, but local amendments vary from town to town, so ask your engineer for the code edition each municipality has adopted.

Illinois is not a high-seismic state for most of its area, but southern Illinois sits near the New Madrid seismic zone, and seismic design categories rise toward the south. Snow drift on low roofs next to high roofs is a frequent Chicago-area structural comment. Neither changes the licence rule; both change the calcs and therefore the fee.

04Illinois seal costs: the arithmetic

We apply the house formulas, then the 1.35x Illinois multiplier for SE-mandatory review. These are typical 2025-2026 market ranges; check every figure against a written quote.

Worked example: an Indiana design-build contractor adds a $300,000 steel mezzanine to a plant in Rockford. Its in-house PE seals mezzanines in Indiana routinely. Base fee: $300,000 x 0.012 = $3,600, so the $3,800 floor applies. Illinois multiplier: $3,800 x 1.35 = $5,130. If the contractor's own engineer pursues an Illinois SE licence and firm registration, add $425, but only if that engineer has passed the 16-hour SE exam. Otherwise the realistic path is to engage an Illinois SE at about $5,130 for this job. Run your own scope in the PE stamp and plan review fee calculator.

05Midwest staffing and CAD rates around Chicago

Illinois engineering demand clusters in three places: Chicago and its suburbs (A&E firms, food and consumer products, logistics), the Peoria and Quad Cities heavy equipment corridor, and Rockford aerospace and machining. Agency bill rates commonly sit in the middle of the national $72-$135 per hour band, lower downstate than in Chicago.

The formula: bill rate = base wage x (1 + markup). A design engineer in Peoria paid $55 an hour at a 50% markup bills $55 x 1.50 = $82.50 an hour, about $171,600 a year at 2,080 hours. A 20% conversion fee on the $114,400 annualized base is $22,880. Ask for the fee to step down to zero by 520 billed hours.

For CAD, heavy equipment work runs on Creo, NX and SOLIDWORKS, and many plants have more seats than active users. Before a renewal, pull license server logs and compare peak concurrency with seats paid. A 3D CAD offshore FTE at $18 an hour is $2,880 a month, $3,398 landed with the 18% review buffer; structural steel detailing at $14 an hour is $2,643 a month landed. If the offshore team produces structural drawings for an Illinois project, the Illinois SE of record must review them, so budget SE hours, not PE hours, for that review.

Compare delivery models in the staffing vs outsourcing TCO calculator.

06Illinois R&D credit: 6.5% of the increase

Illinois offers an income tax research credit of 6.5% of qualifying Illinois research expenses above a base, where the base is the average of the prior three years. Because it rewards only growth, a company with flat research spending gets little from it. The credit has been extended several times; check the current sunset date and carryforward period with the Illinois Department of Revenue.

Worked example for a Peoria custom machine builder: W-2 research wages $1,200,000, supplies $250,000, US contractors $300,000. QRE = $1,200,000 + $250,000 + ($300,000 x 0.65) = $1,645,000. Federal credit at about 7.9% = $129,955. With a prior three-year average of $1,400,000, the Illinois excess is $245,000 and the credit is $245,000 x 6.5% = $15,925. Combined: $145,880.

A 25% contingency fee is $36,470. A fixed-fee study with 7 business components is $8,500 + (7 x $1,200) = $16,900, saving $19,570.

Custom machine builders need to watch the funded-research rule under IRC section 41(d)(4)(H). If a customer pays time-and-materials and owns the result, the work is commonly treated as funded and disallowed. Fixed-price machines where the builder bears the risk of the design not working are the stronger claims. Sort your projects by contract type before the study starts.

07Illinois buyer checklist

• For any building structural scope, require an active Illinois SE licence, verified on the IDFPR lookup.
• Check that the firm is registered as an Illinois professional design firm with the right managing agent.
• Do not accept a PE-only seal on a mezzanine, platform or building structure without confirming the exemption with IDFPR or the building official.
• In Chicago, ask whether the engineer uses standard review or self-certification and how many comment rounds the fee covers.
• Ask for the code edition each suburban municipality has adopted.
• Cap agency markups and set a 520-hour conversion step-down.
• Budget SE review hours for any offshore structural drafting.
• For the R&D credit, model the Illinois increment against your three-year average and screen out funded projects.

08Run the numbers: multi-state PE stamp, plan review and NCEES comity fee calculator

The same benchmarks as this sheet, with your inputs. Share link and printable brief open the full calculator page.