A building contains several separate residential units under one roof or within one complex. That property is a multi-family home. Duplexes, triplexes, fourplexes, and larger apartment buildings all fall into the category.

Investors buy multi-family properties for rental income and economies of scale in management and maintenance. Financing terms often change once the unit count exceeds a certain threshold, shifting from residential to commercial lending standards. Owner-occupants sometimes live in one unit while renting the others.

Management intensity rises with unit count. Professional property management becomes more common as buildings grow larger. Zoning and building codes regulate density, parking, and safety systems. Multi-family housing supplies a large share of rental inventory in most cities.

One roof, many households, and a single ownership structure define the asset.