Locating condominium unit boundaries in recorded documents
Understand how to identify the specific physical limits of your Illinois condominium unit by examining the recorded declaration and certified surveyor plats.
The short answer
Defining the boundaries of a condominium unit is critical for maintenance and insurance purposes. Under the Illinois Condominium Property Act, unit boundaries generally include finished surfaces like paint and flooring, while the association is responsible for structural portions. You should rely on the recorded plat, certified by an Illinois Land Surveyor, to determine your precise unit limits.
The Role of the Recorded Plat
A plat certified by an Illinois Land Surveyor is recorded alongside the declaration to define the physical location of units. This document acts as the master reference for your unit's dimensions. If you are unsure where your unit ends and common elements begin, the plat provides the definitive spatial evidence.
Defining Interior vs. Structural Boundaries
Typically, your unit ownership covers internal finishes, such as wall paint, flooring, and carpeting. Conversely, the building's structural elements, such as load-bearing walls, floor slabs, and exterior framing, are classified as common elements. Reviewing the declaration helps define who is responsible for specific types of repairs within your unit.
Separability of Ownership
Illinois law dictates that your unit ownership and its corresponding percentage of common elements cannot be separated. When analyzing the boundaries, remember that you are effectively purchasing a portion of the building structure along with your interior space. This link is non-negotiable under the current Condominium Property Act.
Planning Example: Boundary Audit
Conduct a boundary audit by mapping out your unit’s exterior and interior walls. Use a worksheet to document which surfaces the association is responsible for versus those you maintain. If the plat is difficult to interpret, take it to a qualified contractor or ask the association manager to point out the boundary lines based on the survey.
Checklist
- Request the certified plat recorded with the declaration.
- Identify the specific boundaries mentioned in the unit's legal description.
- Clarify which surfaces are defined as common versus unit-owned.
- Note structural walls or ceilings for maintenance responsibility.
- Ask a professional to clarify any ambiguous survey diagrams.
Common questions
Who is responsible for repairs to a wall shared with a neighbor?
Shared structural components are generally considered common elements. You should check your declaration to see how specific wall boundaries are defined for maintenance purposes.
Does my unit ownership include the space behind the walls?
Usually, your ownership is limited to the interior finished surfaces. Structural portions behind those surfaces, such as plumbing, electrical, and support systems, are often common elements.
Sources
- CFPB — Closing Disclosure explainerChecked October 12, 2026
- Illinois Residential Real Property Disclosure ActChecked October 12, 2026
- Illinois Condominium Property Act — 2025 editionChecked October 12, 2026
- SQFT IO — Listing plans and termsChecked October 12, 2026
This guide is general educational content from SQFT IO, prepared with AI assistance. It is not legal, tax or loan advice. Talk with a licensed attorney, tax professional or lender about your situation. SQFT IO Illinois license 478.027617.