Early settlers often built a small home to live in while constructing their larger, primary house nearby.
In fact, until the 20th century, people with land built as many homes as they wished.
Most of the units were small (about 700 square feet) and poorly constructed.
In the 1930s, many of D.C.’s alley homes were torn down.
Those that remain have been renovated and modernized and are now popular places to live.
A historic precedent for the modern day accessory dwelling unit is the carriage house, or coach house.
By becoming landlords, the owners gained income from their otherwise unused outbuildings.
Automobile garages have a similar history.
Some were originally built with a housing unit upstairs.
Attached and detached garages occupied yard space that might otherwise have been available for ADUs.
Some cities, including Chicago, grandfathered in pre-existing ADUs but only if the residences remained consistently occupied.
In Houstons historic and trendy Heights neighborhood, old and new garage apartments are common and desired.
This article is adapted fromThe ABCs of ADUs, a publication by AARP Livable Communities.
