top of page


Tips from Byung, California Licensed Architect

bk working.jpg


Having an ADU in the backyard is a big decision to make as a homeowner. Once determined, there will be many more choices to make before construction is finally over. Consider an architect as an adviser to help you to make the right decisions from the inception of the project to the selection of the last finish material.
Architects are professionally trained to solve problems and they are good at finding them as well. Experienced architects will listen to you and provide solutions even for the problems that have not occurred yet.

CAD Screen Shot.png


It is common in many cases that owners find something left to be desired after construction is complete. An architect’s job is to minimize that occurrence by helping owners to make thoughtful decisions. Below are some examples of things to consider during the early planning stage.

What is the purpose of having an ADU?

  Some owners want to have additional income with an ADU. Some owners want an ADU as a retirement home after their son or daughter live in the house with grandchildren. In the latter case, accessible ramps and bathrooms become essential aspects of the project and the owner’s personal preferences will dominate the plan layout.

Size matters?

          The budget and dimensions of the backyard might be the governing factors to determine the size of the ADU, but there are more things to consider. For example, losing the majority of the backyard may impact your life style. If space allows, consider securing a reasonable portion of the outdoor area for your private use and then let the size of the ADU follow. Most jurisdictions require impact fees (can be $10,000 or more) if the area of the ADU is larger than 750 sf. Most jurisdictions enforce ADUs to respect the max. coverage ratio of the lot (per the Zoning Ordinance) if the area is bigger than 800 sf.



Where to put the entry?

          An ADU is required to have an independent entry that is connected to the public sidewalk with a hard surface walking path. Consider giving privacy between the house and ADU entries.

Where to put windows?

          In most cases, the distance between the back of the house and the front of ADU is less than 10’. Consider window locations to be related to the windows of the existing house for privacy and noise control.

Do you want a covered porch?

          Who would not love to have a covered porch with a coffee table? Having it will increase the value of the ADU, resulting in more rental income. But it is not just the porch deck to build. It will add more cost to extend the roof over the porch area, so do not forget to put it in the wish list from the beginning.

How much storage space is enough?

An ADU usually does not have the luxury of having ample storage space. Consider an open attic space above the bedroom and bathroom as a storage area. The roof may get taller, but it is still doable within 16’ of the ADU height limit.

Where to put the Air Conditioning Compressor?

This is one of most neglected items but the first thing owners regret not paying attention to. The compressor makes a whining noise when the air conditioning system is running during summer time. It also blows out hot air. Jurisdictions do not allow placing the compressor within the setback – usually min. 4’ from the property line. Consider the locations of the windows and outdoor sitting area before finalizing the location of the compressor.



As a final note, it is the contractor’s job to build what is on the blueprints that were prepared by the architect, and the drawings had better comply with the State and Local Codes as not to create problems during construction – or worse, after construction. More communication between the architect and contractor helps the project to be more successful instead of pointing fingers at each other. Watching over each other’s shoulders during construction in a constructive way is good teamwork and it will serve the homeowners well in the end.

bottom of page