Home Addition Requirements in Illinois
The locality-first answer in one build: Illinois grants NO state general contractor licence above or below any number, so an addition resolves through Chicago's A–E ladder by SINGLE contract value ($500,000 → Class E $300 with a $1,000,000 CGL … uncapped → Class A $3,500 with $5,000,000) or Cook County's $150/$75-per-trade registration or a village's ordinance — with the trade silos attaching per component (the plumbing registration with its Plumber of Record, the IDFPR roofing licence for any roof work, OSFM for any sprinkler head), the entity paperwork every application asks for, and the owner's path: no exemption to claim, only permits and whoever is hired to do the regulated work.
01 The requirements, sourced
- Chicago general contractor licence — five value classes (A–E), annual, with the matching insurance ladder — A City of Chicago general contractor licence 'is required to perform most types of building construction, alteration, repair, and demolition work within the city' (DOB page, verbatim via search index). Classes and caps (application verbatim — the packet prints each class's ceiling as a 'not entitled to engage' bar, abbreviated below to the value itself): A — 'no limitation as to the value of any single contract project', $3,500; B — 'not entitled to engage in construction of any single contract project of value in excess of $20,000,000', $1,800; C — in excess of $10,000,000, $1,300; D — in excess of $4,000,000, $900; E — in excess of $500,000, $300. Insurance (§ 4-36-090 verbatim): CGL at $5M/$3M/$2M/$2M/$1M per occurrence respectively, from an insurer 'with a credit rating of B+ or higher by A.M. Best Company', with '30 days' advance notice to the commissioner prior to cancellation or lapse', the City 'as an additional insured on a primary, non-contributory basis', and 'A single violation of this section shall result in suspension or revocation … in accordance with section 4-4-280'. Term (§ 4-36-070): 'payable annually … shall expire one year after issuance'. The Commissioner MAY require an online training programme completed by a licensee employee in the preceding 12 months (§ 4-36-065). No examination appears on the City's application. S-IL-CHI-GC-APP
- Unincorporated Cook County — contractor registration by trade: $150 initial + $75 per trade per year, $1M general liability — County page verbatim: 'All contractors performing work in unincorporated Cook County are required to register with the Cook County Department of Building and Zoning.' 'The initial registration fee is $150 per trade. To keep your registration active, there is an annual fee of $75 per trade due by December 31 each year.' Every lane needs '$1,000,000.00 in General Liability' naming the County as certificate holder. Trade conditions: electrical — a supervising electrician's licence from an Illinois city/town/village 'that has an electrical commission that administers an examination'; plumbing — 'Only a corporate officer holding the state plumbing license for the corporation may register', with the IDPH plumbing contractor registration, a State Plumber or Chicago Journeyman Plumber's licence, three completed-installation and three business references; roofing — 'a State of Illinois Roofing License must be submitted'; demolition — an approved bond; crane operators — City-of-Chicago-recognised certification, notarised, non-transferable. Homeowners register free as 'General' contractors, residing on the property, with $1M homeowner GL naming the County as additional insured. Initial registration is IN PERSON (application PDF). S-IL-COOK-REG
- No state general contractor licence and no state home improvement registration exist (verified absence) — Illinois issues NO state general contractor licence and NO home improvement contractor registration. Evidence assembled from official surfaces machine-read 2026-10-11: (1) IDFPR's official profession list (profs/proflist.html) names exactly five construction-adjacent professions — Architect, Home Inspection, Landscape Architect, Qualifying Party Roofing Contractor and Roofing Contractor — and no general contractor, home builder or contractor-profession entry; (2) the Home Repair Act (815 ILCS 510, §§ 5–30 read on the FindLaw mirror) is a REMEDIAL CONSUMER STATUTE ONLY — it defines 'home repair' and prohibited practices, gives the customer a private right of action (§ 15) with attorney's fees (§ 20) and empowers Attorney General enforcement (§ 25), but creates NO licence, NO registration, NO fee and NO qualifying party; (3) IDPH enumerates only plumbing trades and OSFM only fire sprinklers. General building work in Illinois is therefore licensed ONLY locally (Chicago DOB's five-class GC licence; village and city ordinances) or not at all. S-IL-IDFPR-PROFLIST
- Owner-builders: Illinois has NO state owner exemption to grant — there is no state GC licence to be exempted from — Because Illinois issues no state general contractor licence (REQ-IL-NO-GC-001), there is nothing for an owner building on their own property to be exempted FROM at state level. What remains: the trade credentials still bind whoever performs the regulated work — a homeowner doing their own plumbing does not escape the IDPH plumber/licensing structure if the work is 'for another person', and a homeowner hiring a roofer must hire a licensed IDFPR roofing contractor; and every permit and inspection duty stays local (REQ-IL-PERMIT-LOCAL-001). Cook County lets homeowners register FREE as 'General' contractors on their own permits ('Homeowners can perform work themselves, but have to be registered and listed on the permit… They must reside on the property being permitted at the time'). S-IL-COOK-REG
- Entity registration and Assumed Business Name (805 ILCS 405) filings required by every state application — The IDFPR roofing, IDPH plumbing-contractor and OSFM sprinkler applications all require entity proof: SOS Articles of Incorporation / Certificate of Authority (foreign entities) or partnership/sole-proprietor documentation, FILED assumed-name papers under the Assumed Business Name Act (805 ILCS 405) where a trade name is used, and — for corporations/LLCs — current SOS good standing. Cook County adds the previous year's annual domestic corporation report on its plumbing lane. S-IL-RF-APP
02 Which credentials this project can touch
| Credential | Relation | Rule | Source |
|---|---|---|---|
| Licensed Roofing Contractor — Limited (residential) | component basis | IL-ROOFING | S-IL-RF-APP |
| Chicago General Contractor — Class A (unlimited value) | may require | IL-CHI-GC | S-IL-CHI-GC-APP |
| Chicago General Contractor — Class E (up to $500,000) | alternative | IL-CHI-GC | S-IL-CHI-GC-APP |
| Cook County 'General' contractor registration (other trades + homeowners) | alternative | IL-COOK-REG | S-IL-COOK-REG |
| Plumbing Contractor registration (IDPH) | component basis | IL-PLUMBING-CONTRACTOR | S-IL-PC-APP |
Each row is one (project, classification, relation) triple the research record can source — the rendered sections and the seeded evidence can never disagree.
03 Deterministic rules applied
- IL-CHI-GC
- IL-COOK-REG
- IL-NO-STATE-GC
- IL-OWNER-BUILDER
- IL-PLUMBING-CONTRACTOR
Illinois has no conflict rows (the research pass found no official-vs-official disagreement), so this page publishes no conflict notice — the eleven named gaps live on the fees page's withheld list instead.
04 What it costs
| Fee | Amount | Source |
|---|---|---|
| Cook County contractor registration — initial, per trade County service page verbatim: 'The initial registration fee is $150 per trade.' Initial registration is filed IN PERSON by the owner or a corporate officer (application PDF); homeowners' 'General' registration is free of charge. | $150 | S-IL-COOK-REG |
| Roofing contractor licence — application (Limited and Unlimited alike) RF application packet verbatim: 'Payment of $125.00 in the form of a U.S. check or money order made payable to IDFPR', and the checklist's 'An application fee of $125' — the SAME price for Limited and Unlimited (packet machine-read 2026-10-11). Fees are non-refundable; the application 'is active for three years from the date of receipt by the Department' and the Department asks applicants to 'allow eight business weeks'. | $125 | S-IL-RF-APP |
| Roofing contractor licence — renewal price NOT PUBLISHED on the application (cycle verified) PRICE WITHHELD BY NAME (research §O.1): the RF packet prints the $125 application fee and the biennial term ('The license will expire on December 31st of each odd numbered year regardless of when it is issued') but NOT the renewal price, and no IDFPR page read this session published it — unofficial secondary sources circulate $150/$300 figures and NONE was verified, so this row records the duty with amount 0 = 'unpublished', never a guess. See RENEW-IL-ROOFING for the verified cycle. | not published | S-IL-RF-APP |
| Fire sprinkler contractor licence — initial (2-year licence) Application fee table p. 4 verbatim: 'Initial License (2-year license) $3,000' — the most expensive Illinois state construction credential. 'Do not remit fees with application. Once your application has been reviewed and approved, you will be invoiced for the applicable fees.' | $3,000 | S-IL-SFM-APP |
| Fire sprinkler contractor licence — renewal on or before the expiration date Application fee table verbatim: 'Renewal of License (before or on expiration date) $3,000'. Continuing education is required for renewal (OSFM approved-provider list). | $3,000 | S-IL-SFM-APP |
| Fire sprinkler contractor licence — late renewal (up to one year after expiry) Application fee table verbatim: 'Late Renewal of License (up to a year after expiration; includes a $500 late filing fee) $3,500'. The $500 late component is printed inside the row itself — after the year, the licence is expired rather than late. | $3,500 | S-IL-SFM-APP |
| Fire sprinkler contractor licence — duplicate or corrected licence Application fee table verbatim: 'Duplicate or Corrected License $50'. | $50 | S-IL-SFM-APP |
| Chicago general contractor licence — Class A (no value limitation), annual DOB application classification block verbatim, cross-checked against the codifier's § 4-5-010 table: '$3,500' per year. § 4-36-070: the fee 'shall be payable annually. A general contractor license shall expire one year after issuance.' | $3,500 | S-IL-CHI-GC-APP |
| Chicago general contractor licence — Class B (contracts over $20,000,000), annual DOB application verbatim: '$1,800'; § 4-5-010 indexed snippet cross-check verbatim: 'General Contractor, Class B (Chapter 4-36). – $1,800.00 (1 year)'. | $1,800 | S-IL-CHI-GC-APP |
| Chicago general contractor licence — Class C (contracts over $10,000,000), annual DOB application classification block verbatim: '$1,300' per year. | $1,300 | S-IL-CHI-GC-APP |
| Chicago general contractor licence — Class D (contracts over $4,000,000), annual DOB application classification block verbatim: '$900' per year. | $900 | S-IL-CHI-GC-APP |
| Chicago general contractor licence — Class E (contracts over $500,000), annual DOB application verbatim: '$300'; the floor of the Chicago value ladder — and the class whose § 4-36-090 insurance floor is $1,000,000 per occurrence. | $300 | S-IL-CHI-GC-APP |
| Chicago plumbing contractor licence — annual (MCC ch. 4-336) Codifier § 4-5-010 indexed snippet verbatim: 'Plumbing Contractor (Chapter 4-336). – $150.00 (1 year). $150.00 (1 year)'; § 4-336-040: 'The license fee shall be as set forth in Section 4-5-010 of this code.' This City fee STACKS on the $150 IDPH state registration (FEE-IL-PC-ANNUAL-001) — two $150 duties for the same Chicago plumbing business. | $150 | S-IL-CHI-4-5-010 |
| Chicago electrical contractor licence — annual, all classifications (MCC ch. via § 4-5-140) Codifier § 4-5-140 annual-adjustment snippet verbatim: 'Electrical Contractor, all classifications … $150.00 (1 year). $150.00 (1 year)'. The chapter number and the Electrical Supervisor / journeyman / master fees could NOT be machine-read this session (research §O.7) — flagged, never guessed. | $150 | S-IL-CHI-4-5-010 |
| Plumber licence — fee after passing the state examination IDPH 'Retired Plumber's License Application' verbatim (read via the official page's indexed text 2026-10-11): 'apply for the plumber examination with the proper fee ($100) and successfully pass the exam. After passing the exam, the fee for a plumber license is $100.' The plumber and apprentice RENEWAL prices are not on any page read this session (research §O.4) — no renewal fee row is seeded. | $100 | S-IL-PHL-LIC-FEE |
| Plumbing contractor registration — annual (initial and renewal alike) Application body verbatim: '$150 annual registration fee (Registration fees are non-refundable.)'; the IDPH page independently states that 'All plumbing contractors must register with the state and pay an annual fee'. The company registers, the named Plumber of Record carries the competency. | $150 | S-IL-PC-APP |
| Plumbing contractor registration — reinstatement / late fee Form footer verbatim: 'Reinstatement/Late Fee: $100'. The form warns that a late filing suspends the registration and forces re-registration at that penalty; the footer also prints 'Returned Check Fee: $200'. | $100 | S-IL-PC-APP |
| Plumbing contractor registration — returned check fee Form footer verbatim: 'Returned Check Fee: $200'. | $200 | S-IL-PC-APP |
| Plumber state examination — application fee (Illinois apprentice route) Official IDPH examination application verbatim: 'FEES ARE NON-REFUNDABLE. Application Fee for Illinois Licensed Apprentice Plumber: $175.' The parallel line for plumbers registered/licensed in Chicago or out of state is CUT in the retrieved snippet (research §O.3) — no second amount is asserted. Due 30 days before the examination date (225 ILCS 320/10(d)); retakes use the separate Examination Retake Form plus the applicable fee. | $175 | S-IL-PHL-EXAM |
| Cook County contractor registration — annual renewal, per trade County service page verbatim: 'To keep your registration active, there is an annual fee of $75 per trade due by December 31 each year. If you have not renewed your registration in at least two years, please contact the Department…' — the two-year gap is when the registration is treated as lapsed rather than merely late. | $75 | S-IL-COOK-REG |