Vernon Hills — Ch. 5 Art. III One and Two Family Dwelling Code § 5-64
Appendices
Operative Text
The following appendices of the International Residential Code are hereby adopted by reference: (a) Appendix BC--Accessory Dwelling Units (ADU), subject to the requirements of Appendix C, Zoning, of the Village Code. (b) Appendix BE--Radon Control Methods, to also be in accordance with Illinois Public Act 97-0953. (c) Appendix BF--Patio Covers (d) Appendix BO--Existing Buildings and Structures (i) Section BO101.2 shall be inserted to read as follows: Section BO101.2 Automatic sprinkler systems. In the adoption of this appendix BO, it is the intent of the Village that Section R309 shall apply: automatic sprinkler systems shall not be required for additions or alterations in existing structures subject to the IRC that do not have an automatic sprinkler system installed. However, in the event of substantial improvements (as defined in R202) or additions equal to 110% or more of the existing floor area per the definition in the zoning code, the requirements for new construction shall apply. The Village may at its discretion require documentation to support cost estimates and market value estimates per the definition of substantial improvements. (e) Appendix CA--Sizing and Capacities of Gas Piping (f) Appendix CB--Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods, Category I Appliances, and Appliances Listed for Use and Type B Vents (g) Appendix CD--Piping Standards for Various Applications
Vernon Hills § 5-64 formally incorporates several appendices from the International Residential Code (IRC) into local law, covering topics such as accessory dwelling units, radon control, patio covers, existing buildings, and gas and venting systems. The ADU appendix is subject to the Village's own zoning rules, and the radon appendix must also comply with Illinois Public Act 97-0953. For existing structures, automatic sprinkler systems are not required for ordinary additions or alterations unless the project constitutes a 'substantial improvement' or an addition of 110% or more of the existing floor area, at which point new-construction standards apply.
Plain English — not legal advice.
Under Vernon Hills § 5-64, operators of one- and two-family dwellings should be aware that projects involving accessory dwelling units, radon mitigation, patio covers, gas piping, or venting systems are governed by the specific IRC appendices adopted here. When planning work on an existing structure, compliant operators generally track whether a project crosses the 'substantial improvement' threshold or the 110% floor-area addition threshold, since either triggers full new-construction requirements including sprinkler standards. The Village retains discretion under § 5-64 to request supporting documentation for cost and market-value estimates used in that determination.
General guidance for property managers — not legal advice for your specific situation. Consult an attorney for advice on your case.
Vernon Hills § 5-64 affects tenants in one- and two-family dwellings by establishing the building standards that govern construction, renovation, and safety systems—including radon control methods aligned with Illinois Public Act 97-0953—in their homes. Tenants who have concerns about whether work performed on their dwelling complied with these adopted IRC appendices may raise those concerns with the Village's building or code enforcement department. Tenant-rights organizations can also help residents understand how local building code standards under § 5-64 may relate to habitability rights.
General guidance for tenants — not legal advice for your specific situation. Consult a tenant-rights organization or attorney for advice on your case.
Generated November 10, 2026 — auto-generated, not yet human-reviewed. See /transparency for methodology.
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