---
title: "Decide whether an item is common area or a separate interest"
url: "https://ailawframework.com/practice/strata-and-community-titles/decide-whether-the-item-is-common-property-or-lot-property/united-states"
type: "task_jurisdiction_version"
site: "AI Law Framework"
id: "A47-X20260927-7-US"
practice_area: "Strata & Community Titles"
tier: "red"
lawyer_review: "required"
jurisdictions: ["US"]
last_reviewed: "2026-10-22"
---

# Decide whether an item is common area or a separate interest

> Extract the declaration's boundary language and the condominium plan's legend into a table beside the item in dispute. Do not decide who must maintain or pay for it.

Canonical page: https://ailawframework.com/practice/strata-and-community-titles/decide-whether-the-item-is-common-property-or-lot-property/united-states  
Last reviewed: 2026-10-22

Site index for agents: https://ailawframework.com/llms.txt

## Key facts

| Fact | Value |
| --- | --- |
| Practice area | [Strata & Community Titles](https://ailawframework.com/practice/strata-and-community-titles.md) |
| Human involvement | Red: Lawyer writes; AI may check, clarify or collect data |
| How AI is used | Extract the declaration's boundary language and the condominium plan's legend into a table beside the item in dispute. Do not decide who must maintain or pay for it. |
| What the lawyer must review | In California, Civil Code § 4095 defines common area as the entire common interest development except the separate interests. Section 4185 defines separate interest differently for a community apartment, a condominium, a planned development and a stock cooperative, and, unless the declaration or condominium plan provides otherwise, treats the interior surfaces of designated boundary walls, floors, ceilings, windows and doors as part of the separate interest and the other portions as common area. Section 4145 defines exclusive-use common area and lists fixtures that are exclusive-use common area unless the declaration provides otherwise. You read the recorded declaration and plan and you decide. Another state's definitions are not these sections. |
| Written for | United States |
| Applies to | [Decide whether the item is common property or lot property](https://ailawframework.com/practice/strata-and-community-titles/decide-whether-the-item-is-common-property-or-lot-property.md) |

## Checking plan

- What the AI does: Extract the declaration's boundary language and the condominium plan's legend into a table beside the item in dispute. Do not decide who must maintain or pay for it.
- Basis: Checked against the linked sources on 22 October 2026. Confirm the current instrument before reliance.

## Notes

- The declaration or condominium plan can displace the interior-surface rule in § 4185(b). Read the recorded documents.
- Maintenance duties are often in a different section from the definition. Do not stop at the label.

## Sources

- [California Civil Code § 4095 (common area)](https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CIV&sectionNum=4095) (checked 2026-10-22)
- [California Civil Code § 4185 (separate interest)](https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CIV&sectionNum=4185) (checked 2026-10-22)
- [California Civil Code § 4145 (exclusive use common area)](https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CIV&sectionNum=4145) (checked 2026-10-22)

*Practice guidance for planning and review. Confirm current primary sources and the requirements of the actual matter. This is general information, not legal advice.*