ADU: Accessory Dwelling Units

An Accessory Dwelling Unit (ADU) is a residential unit that can be added to a lot with an existing single-family-home. ADUs can be detached (a separate building in a backyard), attached to or part of the primary residence, or a garage conversion. ADUs are independent rental units that have their own kitchens, bathrooms, living areas, and entrances.
ADU architects can provide additional space for caregivers, grown children, elderly parents, or renters. Because ADUs are rental units, they produce additional household income. “Empty nesters” can stay in their neighborhoods by moving into a smaller ADU and renting their larger existing home to pay the mortgage. An ADU can be built to house a relative or caregiver. There are many reasons for building an ADU on your lot.
The new state law (AB 2299, effective January 2017) applies to LA and makes it easier to build an ADU on a single-family lot. The state law encourages the construction of accessory units because the City needs more housing.

ADU Intro


  1. Detached Unit to the Lot with an Existing Garage.
    You can build up to 1200 sq. ft. with 5 ft minimum from side and rear property lines and 10 ft. minimum between main house and ADU.
  2. Attached Unit as addition to the House.
    No more than 50% of existing house and max of 1200 sq. ft. also it needs to have side and rear setbacks.
  3. Convert the Backyard Garage
    You can build up to 1200 sq. ft. without changing the existing setbacks.
  4. Attached Unit to the Backyard Garage
    Maximum of 1200 sq. ft. with a minimum of 5 ft. from the side and rear property lines. 10 ft. minimum between main house and ADU.

ADU Types

ADU Structure


Every neighborhood in Los Angeles falls under specific zones. To build an ADU, the current house must be located in a residential zone, and most likely in a single family residential zone. ADUs are permitted in all single-family zones. Any lot in these zones, regardless of its size, can add an ADU if it will fit. Your lot must have an existing house, only one ADU per lot is permitted, and the ADU cannot be sold separately from the house. An ADU design must meet additional site requirements as well as building construction.


Many lots already accommodate two parking spaces in a garage or carport. When you add an ADU, you may need to fit one extra parking space on your lot. If an additional space is required, the space may be covered or uncovered.
You may not need additional parking if:

  1. ADU is located more than one-half mile of public transit.
  2. ADU is located within an architecturally and historically significant district.
  3. ADU is part of the existing primary residence or an existing accessory structure.
  4. On-street parking permits are required, but not offered to occupant of the ADU.
  5. There is a car-share vehicle located within one block of the ADU.

These are the five current parking exemptions as of July 2017, but parking requirements may change.


The lot may not need additional parking for the ADU, leaving room for open space, a patio, a bigger ADU, etc. If the lot is located within one-half mile of transit (defined as one-half mile from any bus stop or rail station), it should meet the parking exemption.


Earthquake Retrofitting

Living in California, we are always worry about earthquakes and the damages after them. Earthquake retrofitting keeps houses and buildings from being displaced from its concrete foundation – making the building safer and less prone to major structural damage during an earthquake. Existing homes need to be retrofitted because the understanding of the effects of earthquakes as well as construction techniques have improved after the homes were built.

How earthquake forces can affect buildings in 3 ways

The above diagram shows how earthquake forces can affect buildings in 3 ways.

There are many ways to make sure the house is up to safe.

  1. Foundation Bolting: bolts are added to improve the connections between the wooden frames in the building and the concrete foundation. Careful planning, placement and installation of foundation bolts are critical for good bolting strength. It is important to use the proper type of bolt corresponding to the existing conditions of the home and its foundation. The expected type of bolt load or stress is another important consideration for bolt selection.There are normally two types of foundation bolts – expansion bolts bolt and epoxy-set bolts.
  2. Cripple Wall Bracing: Most houses have a short wood-frame wall in the sub-area crawl space. This wall might be anywhere from a few inches to several feet in height, running upward from the top of the concrete foundation to the bottom of the main floor. This wall is know as the Cripple Wall. Cripple wall collapse is a main source of earthquake related failure. The collapse of this wall often results in the main floor dropping to the ground.
    Stiffening or bracing of the cripple wall to keep from collapsing during seismic movement it is extremely important. The bracing is accomplished by attaching structural grade plywood tightly to the wall framing. This is referred as a Shear Wall.
    The stiffening effect is accomplished in the lengthwise direction of the plywood, which means that plywood runs along the side walls of a house will brace it in the front-to-back direction while plywood run along the front and back walls will brace the house in the side-to-side direction. Accordingly, it is important to brace all sides of a house for the best seismic protection.
  3. Foundation Holdown Bracket: Some houses also require additional holdown brackets to anchor the shear walls. Holdowns are specially constructed right-angle brackets connecting from the cripple wall framing into the foundation. As the bracket name implies, they are designed to resist a shear wall lifting or rolling effect, which may also occur during seismic activity. Generally, the need for holdowns is a function of the height-to-width dimensions of a shear wall configuration.
  4. Home without Cripple Walls: Not all houses have cripple walls. In many newer houses, and some older ones, the floor framing (joist) rests directly on the mudsill. Compared to houses with cripple walls, houses built in this manner are considered to be slightly less vulnerable to displacement from their foundations. There is still significant risk, however. The connection between the floor framing and the foundation consists of a series of “toenails” which are often too weak to withstand strong seismic movement and the house can slide off its foundation. Even slippage of a few inches can do major damage to the house, allowing portions of it to sag and cause structural damage or to sever utility connections such as gas, water, sewer and electricity which extend from the ground into the house.

There are many methods available for improving the connection of the framing to the foundation. The choice of which connecting system is most practical for a given house comes down to a host of variables and ultimately includes a judgment on cost effectiveness. Older homes vary widely in their access conditions, framing size and configuration of the foundation, etc., and there is usually not a “single” correct way to improve this connection.

Two of the most common are Simpson Strong-Tie Retrofit Connectors and Angle Iron Struts and Foundation Bolting.

California’s New Way for Growth in the Housing Market

California has been hit hard with a housing disaster in recent years and now the state’s city bureaucrats have started to restructure laws to make it easier for property owner’s to build accessory, also called alternative dwelling units, and get them approved for permits. People mostly use these alternative dwelling units on their property for additional housing, and a lot of the time also providing property owner’s the benefit of renting it out and getting additional income. It is city laws that have had the more binding and hard-to-comply-with regulations for these units and this is where property owner’s usually get a notice to comply or building code violation.


Los Angeles is Paying homeowners to Build Guest Houses

Now, the cities will have to adopt a new ordinance for these alternative dwelling units that comply with the the state of California’s standards, which are a lot more lenient, instead of the city’s old regulations. This is because Governor Jerry Brown has approved a bill to inspire more housing units to be built, to alleviate the lack of supply in California’s housing market. In addition to this, Los Angeles has taken the bill and also developed what they are calling a “pilot program,” where Los Angeles city government could finance a homeless accessory dwelling unit for three years for an estimated $15K a year. It would also cover 70% of rents done with low-income vouchers, with the tenant creating the remainder.
Property owners who qualify can get up to $75K to fund building for these alternative dwelling units and those who already have these alternative dwelling units on their property can apply for this program in Los Angeles as well, and can receive up to $50K in funding to renovating these properties and renting it out to a person was formerly “homeless.” If only 10% of the homeowners in California (6.8M) create these alternative dwelling units then 600,000 possible units can easily be added to the housing market. These units, which some can cost more that $300K to construct, will be one bedroom apartments and will have full-plumbing and kitchens, along with separate entrances, to building code standards.

Construction Progress 2

Helping Homelessness

This initiative has not yet taken off, but Los Angeles Mayor, Eric Garcetti has been constantly reiterating the major importance these additional dwelling units, or guest houses, will have on the California and Los Angeles housing markets and help the number of homeless, that has been widely growing. There are $58K homeless people in Los Angeles County alone. Finding a home for all of these people has required a lot of not-so-ordinary thinking, as you can see. This is your chance to do you part in Los Angeles’s “Everyone In” Initiative. Ground will start breaking with this project by 2019.

Construction Progress 3

CCS INC wants to be who YOU choose to convert your existing accessory dwelling unit to comply with code standards or be your project manager for your new venture! Call us now at (747) 206-9217!!!