Architecture is one of the most complex subjects since the beginning of human existence. It changed over the centuries. From country to country and even regions and cities one can find different ways of how houses and buildings are constructed. The way of living, the designs, and materials are various. From skyscraper and detached houses to townhouses and tiny houses, everything is possible. People build luxurious Mansions, Palaces, and Villas. There are already existing designs that can be materialized, people can also put all their creativity into a new design. Architects and engineers make sure the construction is stable, strong, and long-lasting.

One construction type that became trending is the Accessory dwelling unit (ADU)

What is an accessory dwelling unit?

ADU describes a building that is on the same ground, whether individually or attached to a single-family house. The ADU shares the building lot of a larger, primary home. The purpose can be various. Many people build an ADU for relatives, grandparents, or parents, so they can live close but still independently. This can be an apartment over the garage, a basement flat, or a separately built house in the backyard. Some people rent their ADU´s to have a little extra income. 

Mostly, the ADU´s count like a part of the main house, so electricity and water are shared with the main house. Rarely water and electricity are separately attached. 

Usually, you can´t buy an ADU by itself because it is part of the main property. Mainly an ADU is given on rent or for family members.

ADU´s are also known as an in-law or mother-in-law units, secondary dwelling units, or granny flats. The regulations of building an ADU are very strict. Landlords have to make sure that they lawfully build the dwelling unit. In otherwise they might have a lot of trouble.

What role plays Soft story retrofit for ADU´s

A soft story retrofit is a structure that has a weak first floor, which means that it can´t hold many constructions. Mostly the ground floor is an open garage or storage and above there might be an apartment or other building. Many ADU´s are built as a soft story retrofit. Experts question the design a lot because it is not seism-proof.

What are the Cons of ADU´s?

An ADU might take space that could have been used otherwise. As the second dwelling units share the property with the main house there might not be much space for a big garden or storage. 

Rental ADU´s require constant maintenance. The house owner has to take care of the apartment, and renovate or renew parts if necessary.

The construction of an ADU needs financial savings, and later the costs can furthermore increase because of higher property taxes, and growing expenditure of water and electricity. 

So, overall one big Con is that an ADU costs a lot of money in construction and for maintenance.

What are the Pros?

ADU´s can give an extra income giving it on rent. They also add value to the main property. And of course, ADU´s give a lot more space for relatives, friends or open up a place for new opportunities like workshops or ateliers.