Accessory Building

Accessory building is a secondary structure located on the same parcel as the primary dwelling and used for the benefit of that dwelling. Common examples include detached garages, tool sheds, barns, workshops, carports, pool houses, and greenhouses. Accessory buildings are distinguished from the main structure by their subordinate function -- they supplement the primary residence rather than serving as independent habitable space.

Why Accessory Buildings Matter to Note Investors

When evaluating a mortgage note, the property securing the loan is your collateral. Accessory buildings can meaningfully influence that collateral's value -- positively or negatively -- depending on their condition, legality, and contribution to the property's overall appeal.

Property Valuation Impact

During due diligence, investors order a BPO (broker price opinion) or appraisal to determine the property's fair market value. Accessory buildings factor into these valuations in several ways:

A property with a solid, permitted detached garage will typically appraise higher than an identical property without one. Conversely, a deteriorating outbuilding that poses a safety hazard or code violation can drag value down and complicate an REO disposition.

Condition Assessment

When reviewing exterior property photos from a BPO or drive-by inspection, pay attention to accessory buildings as indicators of overall property maintenance. A well-kept outbuilding suggests an owner who invests in the property. A collapsed roof on a detached garage may signal broader deferred maintenance on the primary structure as well.

Common Types of Accessory Buildings

• Detached garage -- the most common accessory building, often contributing the most to property value
• Storage shed -- small structures for tools and equipment; minimal value impact unless oversized or commercial-grade
• Barn or stable -- relevant on rural or agricultural properties; can significantly affect value in those markets
• Workshop -- may add value if properly built and permitted, especially in markets where buyers value hobby or trade space
• Carport -- open-sided covered parking; modest value contribution
• Pool house or cabana -- common in warmer markets; adds value when the pool itself is in good condition
• Accessory dwelling unit (ADU) -- a habitable secondary unit (guest house, in-law suite) that may generate rental income; these carry distinct zoning, permitting, and valuation considerations beyond a simple accessory building

Zoning and Permitting Considerations

Most municipalities regulate accessory buildings through zoning ordinances that specify maximum square footage, height limits, setback requirements, and lot coverage ratios. An accessory building that violates these rules may be unpermitted, which creates risk for the note investor:

• Insurance complications -- unpermitted structures may not be covered by the borrower's homeowner's insurance
• Title issues -- a code enforcement lien filed against the property for an unpermitted structure affects title and can complicate foreclosure or sale
• Demolition costs -- if the municipality requires removal of an unpermitted structure, that cost reduces net recovery on the asset

Practical Takeaway for Note Investors

Accessory buildings rarely make or break a note investment decision, but they are part of the collateral picture. During property value and condition review, note any accessory structures in the BPO photos and property description. Factor their contribution -- or liability -- into your valuation model. If you end up taking the property back through foreclosure or deed in lieu, the condition and legality of every structure on the lot will affect your disposition strategy and timeline.