Definition
An outbuilding is a structure that is separate from, and subordinate to, a principal building on the same parcel of land. The term most commonly appears in property law, deed restrictions, and zoning ordinances, where it describes ancillary structures such as stables, barns, sheds, garages, and similar secondary improvements. The key characteristics are physical separation from the main structure and a functional relationship to it — the outbuilding serves the principal use of the property rather than constituting an independent use in its own right.
In restrictive covenant analysis, whether a structure qualifies as an outbuilding often determines whether it falls within permitted exceptions. A covenant permitting "dwellings and necessary outbuildings" extends coverage to secondary structures reasonably necessary to support the primary residential use. A structure that is separate and subordinate but not functionally connected to the principal building — or one that serves only a temporary or incidental purpose — may not qualify.
Common Language
Modern common usage (Wiktionary): Wiktionary treats "outbuilding" only as a verb form (present participle of "outbuild"), which is not the sense encountered in legal materials.
Historical common usage (Webster's 1913): "A building separate from, and subordinate to, the main house; an outhouse."
The Webster's definition closely tracks the legal meaning in most contexts, but legal sources add a layer of functional analysis that the dictionary definition omits. In restrictive covenant and zoning disputes, courts look beyond physical separateness to ask whether the structure is reasonably necessary to the primary use. A building that is technically subordinate may still fall outside the permitted category if its connection to the principal use is too attenuated or temporary.
Common Confusion
Outbuilding and outhouse are sometimes used interchangeably in older sources, but in modern property law "outhouse" most often refers specifically to a privy or sanitation structure, while "outbuilding" carries the broader meaning of any secondary structure. Researchers encountering "outhouse" in historical deeds and restrictions should not assume it is limited to that narrow modern sense — in nineteenth-century usage it often meant what we would today call an outbuilding. The Bouvier entry cross-references "OUT-" entries, reflecting the older usage pattern.
Why It Matters in Research
The operative question in most outbuilding disputes is definitional: does a given structure qualify? Courts have answered this contextually, and the Massachusetts cases Bouvier cites illustrate the point. A stable connected to a residence may be a necessary outbuilding under a deed restriction; the same stable built to serve a temporary tent structure on the same land may not qualify. Researchers analyzing restrictive covenant disputes should look closely at what the primary use of the property was at the time the structure was built, not just at the structure's physical characteristics.
Zoning codes have largely supplanted deed restrictions as the primary regulatory framework for secondary structures, and modern zoning terminology often uses "accessory structure" rather than "outbuilding." These terms overlap substantially but are not identical: an accessory structure in a zoning code is a defined term with specific dimensional and use limitations that may differ from what a nineteenth-century deed restriction would have contemplated as a necessary outbuilding. Researchers should not assume that judicial interpretations of "outbuilding" in old covenant cases translate directly into modern accessory structure analysis.
Historical deed restrictions using "necessary outbuildings" language appear frequently in late nineteenth and early twentieth century residential subdivision instruments. When researching chains of title or covenant enforceability in that period, the presence of this phrase creates a fact-intensive interpretive question that may require consulting contemporaneous local practice and case law rather than relying on a single dictionary definition.
Historical Dictionary Support
Bouvier's defines outbuilding functionally — something used in connection with a main building — and immediately grounds the definition in Massachusetts case law rather than abstract principle. This approach reflects the term's character: it is not a term of art with a fixed technical meaning but a descriptive category whose boundaries are determined by context.
Bouvier's citation to 140 Mass. 287 establishes the basic rule that an outbuilding is something used in connection with a main building. The citation to 159 Mass. 6 introduces the necessary qualification: the connection must be genuine and not merely incidental or temporary. A stable built for a tent does not satisfy the functional requirement even if it satisfies the physical one.
Webster's 1913 tracks the legal meaning closely for ordinary purposes but, as noted above, omits the functional necessity analysis that courts apply in restrictive covenant cases. Historical legal dictionaries generally treat this as a practical, context-dependent term rather than one requiring elaborate doctrinal treatment, which is accurate — but researchers should not mistake simplicity of definition for simplicity of application.
Jurisdictional Note
Zoning codes vary widely in how they define and regulate secondary structures. Many jurisdictions use "accessory structure" or "accessory building" as the operative regulatory term, with specific provisions governing setbacks, size limits, and permitted uses. Researchers working with modern regulatory materials should identify the applicable zoning definition rather than relying on the common law meaning of outbuilding.