The dangers of a prefab ADU in Los Angeles

Accessory Dwelling Units are growing in popularity and there are various ways to get your construction project moving quickly. There is however a danger of moving too fast, and one of the options being offered is the prefab ADU, a ready-made modular unit. It brings the promise of saving money and time when it comes to installation, but we strongly recommend against it! The prefab ADU comes with hidden costs that can cause your project a major setback. ARM Builders believe in sharing everything up front and offering you the best possible advice so that your ADU project is set up for maximum success.

The prefab accessory dwelling unit sounds like a great idea – you look in a catalogue, order your off-the-shelf unit and have it built in your backyard. The first major problem is that there are various hidden costs that the city requires, such as laying a completely new foundation. In addition, you will lose the use of land around your property and there is a lack of flexibility when it comes to your long-term plans for the ADU. At ARM Builders we recommend against going with the prefab ADU option, since there are many other cost-efficient and more effective methods of construction.

UTILISE YOUR EXISTING GARAGE FOR AN ADU CONVERSION

A great place to start with your accessory dwelling unit in Los Angeles is to aim for an ADU garage conversion that takes your existing structure and converts it into a legal, liveable unit. One brilliant opportunity offered by the ADU legislation is that your new conversion can even be two storeys, which can provide excellent living space in addition to boosting the valuation of your property. On the other hand, if you went for a prefab unit then it would not be customized to your existing garage, and you would need to put it up in a separate area which would unnecessarily eat up more land in your backyard. Any gains from getting a unit with lower construction costs would potentially cost you more in the long run because you’ll lose access to a portion of your backyard, and there is little to no flexibility if you want to make changes to the design of your prefab unit further down the line.

MAKE THE MOST OF YOUR PROPERTY LINE AND AVOID ‘DEAD SPACE’

Land space is everything, especially in Los Angeles, and with space at a premium it is no surprise that most garages are built almost on the property line with the neighbour. This makes sense because there is no ‘dead space’. There is, however, a big problem that occurs when it comes to prefab ADU units. The city building code demands that a prefab unit has to be installed five feet from the sideline and 10 feet from the back line of the property, which means that you will immediately lose at least 100 square feet from the side yard and 200 square feet from the back, totalling 300 square feet of lost space from your backyard. In the past you would see that garages were built as close as possible to neighbours, and these property layouts have been grandfathered in since they were legal at the time. Once you choose a new prefab unit you will lose all ‘grandfathered’ rights, and along with it you will lose the benefits of your extra space. This is another important reason why ARM Builders recommends converting your existing garage to an ADU, or choosing a new design for your accessory dwelling unit.

ENERGY CONSERVATION AND TITLE 24 ENERGY REQUIREMENTS FOR ADUS

Los Angeles has one of the strictest energy conservation requirements in the country, and California’s energy code is designed to reduce wasteful and unnecessary energy consumption in newly constructed and existing buildings. This points to yet another problem with prefab ADUs that are made all over the country, since they may not adhere to the stricter requirements of Los Angeles. California Title 24 Building Energy Efficiency Standards were designed to promote sustainability, and reduce energy consumption. An example of this might be the need for more efficient insulation, regulations around water conservation, or HVAC/air conditioning efficiency requirements. The ultimate nightmare would be to have a prefab ADU installed and then to find that you somehow have to retrofit elements so that they are compliant with the California title 24 energy conservation code! At all costs…avoid a prefab ADU!

AVOID HIDDEN FEES FROM CONTRACTORS

We’ve all heard about customers getting unexpected bills from unscrupulous contractors, which is why we believe in integrity, openness and cost transparency at ARM Builders. Many prefabs will require a local contractor to pour a foundation which will accommodate the prefab unit, but companies selling the prefab ADU unit generally won’t include this cost within the pricing. The customer will have to pay for the foundation, the excavation, the steel and the concrete, and this could be a very unpleasant surprise if it is not included in the prefab pricing that they received at the start of the process. Costs can range from $15,000 to $20,000 to lay a foundation, and there will be additional costs to connect your unit with existing utility systems like plumbing, water, electrical, sewage & gas.

Building an ADU can be a game-changer for your property, but it is important to do it right and hire the best possible contractor to guide you through the process. Get in touch with ARM Builders for a free on-site or virtual consultation.

ARM Builders, Inc. · CSLB Lic. #915352 · 877.755.1350 · armbuildersinc.com