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Mighty Buildings, ADU Guide

ADU Guide

Mighty Buildings is a modular prefab construction company providing turn-key installation services. By utilizing 3D printing technology and our Light Stone Materials, we assemble modular houses faster than traditional construction. Our units are fully compliant with all aspects of the California Building Code, including Title 24 Energy and other standards.

We provide a turn-key solution for Accessory Dwelling Units (ADUs), which means we assemble the permit packages, get permits approved, pour the foundation, connect the utilities, and install the unit ourselves. Think of our turn-key solution as a one-stop shop.

Mighty Buildings

Land Use Entitlements
Delivery & Installation
Building Permits
Utilities Connections


ADU is an accessory dwelling unit, a detached or an attached building that goes into a backyard or a side yard of an existing residence. ADUs are usually built as a guest house or extra living space on the property for rental purposes or as a long term investment.

ADUs are an extension of your property so it does increase your property value. However, the property tax goes up insignificantly by the amount of construction costs added to the base of your assessment value.
Depends On The Jurisdiction
4-8 months
Varies Heavily Between AHJ
60 days
Primary Residence
Do You Have An Existing House?
Mighty Duo B
Mighty Duo B interior
While these new laws have done a great deal of work in standardizing the accessory dwelling unit requirements statewide, local jurisdictions still have a lot of ability to control the types of ADUs in their area. For instance, design requirements may still be a factor in specific locations. Feel free to reach out to your Mighty Buildings representative to check specific properties for their local requirements.

New ADU State Laws

On October 9th 2019, Governor Gavin Newsom signed a series of bills opening up ADU's statewide. These bills went into effect on January 1st 2020 and dramatically loosened the restrictions for building ADUs throughout the state. The main purpose of these bills is to standardise the regulations for ADUs.
Remove minimum lot size requirements
Remove minimum lot size requirements
Allow up to 2 ADU's in multi-family zones
Allow up to 2 ADU's in multi-family zones
Eliminate impact fees for units less than 750 sq. ft.
Eliminate impact fees for units less than 750 sq. ft.
Mandate setbacks to a maximum of 4 ft from side and rear property lines
Mandate setbacks to a maximum of 4 ft from side and rear property lines
Place a 5 year moratorium on owner occupancy requirements
Place a 5 year moratorium on owner occupancy requirements
Eliminate lot coverage requirements for units under 800 sq. ft.
Eliminate lot coverage requirements for units under 800 sq. ft.

Pre-approved plans / Factory Built Housing

Factory Built Housing is exactly what it sounds like. It is a program put in place by California's Department of Housing Community Development to allow the assembly and construction of portions, or the entirety of a construction project be built offsite as a method to reduce cost and weather delays. Once onsite and installed, there is essentially no difference between a Factory Built House and a traditional built house. These units are inspected at the factory, but installations are inspected by the local jurisdiction.

All our designs are reviewed at the State level and come with a pre-approval at the authoritative housing jurisdiction level. This means that when the permit package is submitted to the local jurisdiction, they only review site specific details, such as the foundation, utility connections, and installation plan for the unit, creating less confusion and much quicker straight forward plan review.

For more information on the Factory Built Housing Program refer to this HCD Manual.
Mighty Trio Interior Plan

Why Build an ADU?

The best time to build is now. ADU's are an investment for your property and provide financial security in a slow housing market or economic downturn. In fact, an ADU can be one of the safest investments you can make. It is a direct investment into your current property and during a downturn, it can increase the value of your property. In addition to the sizable increase to your property, you can gain the potential rental income, which gives you a steady flow of income during unprecedented times.
Comparison table Build an ADU
Increase your property value by 30%
Increase your property value by 30%
Recession proof your new mortgage
Recession proof your new mortgage
Rates are historically low
Rates are historically low
Higher ROI than a traditional remodel
Higher ROI than a traditional remodel
Multiple models to accommodate virtually any size yard
Multiple models to accommodate virtually any size yard

Benefits of ADUs?

Price vs cost
All our ADU's come complete with state of the art 3D printed technology, high end appliances, Anderson windows and doors, stone countertops, tankless water heater, central heating and air, and even solar panels. Mighty Buildings' industry leading 10-year warranty shows our dedication to the quality of construction and craftsmanship. In comparison to other ADU units in the market without turn-key solutions, we truly believe you get the quality you pay for and in the end, you will save on the overall cost of your new ADU.
An end-to-end process
Our end-to-end service includes permitting, site evaluation, construction, delivery and setup, and financing. This saves you time and money as you don't have to get involved in the time consuming process of ensuring your new ADU is built to code. Our project managers and compliance officers guarantee that all the required documentation will be completed and filed in accordance to state and local guidelines.
Property Values
A recent University of Oregon study showed that an ADU can increase the value of your property more than 20% over a traditional full home remodel. In addition, you gain valuable additional living space that a typical remodel would not be able to provide.
Rental Income
One of the most sought after benefits of an ADU is the ability to rent it out and generate a steady monthly income. Unlike adding a guest room to your existing home, renters are separated from your main residence. This allows you to monitor and maintain the ADU without sacrificing your privacy.
Rates are currently at historic low levels and Mighty Buildings has several loan programs that can assist you in purchasing your new ADU. Even if you were planning to pay in cash, a short discussion with our financing team could provide valuable options.
ADU Laws
On January 1, 2020 a series of laws went into effect that revise and relax the laws governing ADUs. The new laws are intended to help address the housing shortage in California and make ADU development easier. For developers, investors and homeowners these laws will open up a range of investment possibilities.

ADU Regulations

Check city requirements to build an ADU

How To Finance an ADU

Today, we partner with a number of lenders: Quicken Loans, Umpqua Bank, Patelco Credit Union. Our goal is to match our client's specific needs with one of our lending partners as each request is unique. There are a number of different loan options we use to provide funding to our client to finance their accessory dwelling unit.
Home Equity Line of Credit
Construction Loan
Cash out Refinance
Personal Loan

An Overview of MB Products

As previously mentioned, Mighty Buildings is a prefab modular builder. All of our models have been pre-approved at the State level by California's Department of Housing and Community Development under the Factory Built Housing (FBH) program.
864 sq.ft. Total
2 bedrooms
1 bathroom
24' x 36'
1176 sq.ft. Total
2 bedrooms
2 bathroom
24' x 49'
1440 sq.ft. Total
3 bedrooms
2 bathroom
24' x 60'

Our Turnkey Process

Sit back and relax while we deliver and install your unit!
Truck delivery, craning, and onsite work for utility connections.

Foundation completed: 30% of APP.

Assembly of kit completed: 10% of APP.

Final inspection and signature of Bill of Sale.
1 month
Delivery & Installation
Submit planning/zoning plan: 5% of APP.

Submit building plan: 10% of APP.

Building plans approved: 40% of APP.

The Mighty Unit fabrication begins.
2-4 months
Permitting Process
Entitlement Services
1-2 months
Sign the Buyer's Contract to prepare your Delivery Roadmap.

Site specific documentation and reports required for permits are created, including a soils report, a property survey, architectural, structural, and MEP drawings.
Customer signs contract and pays a retainer of $15K
Schedule a Site Assessment
Your zoning and setback information to confirm feasibility of the project.

In-person site visit by a GC.

Site plan of the ADU on your property.

Estimated project budget for turnkey site work

*Deposit is non-refundable after site visit.
The first step in determining which unit is best for your property. $1,000 deposit includes:
Сustomize your Mighty Unit from the options on the website.
We will conduct a feasibility study to determine if your property and location is approved for an ADU.
Click and go!
Customization. Click and go!
Site Assessment
Entitlement Services
Permitting Process
Delivery & Installation

MB tech advantages vs concrete 3D printing

Mighty Buildings uses 3D printing technology and proprietary Light Stone Material such as reinforced concrete, as an alternative to conventional building materials. Beyond the structural and other physical properties, the material replaces several layers of material as it can work as structural, exterior, and interior material.

Our Light Stone Material eliminates cold joints between layers, which occur when the specific temperature and humidity requirements for proper curing of concrete are not met. We are able to achieve this due to the rapid solidification of our material under UV light, thus avoiding the structural issues when the material is solid and subjected to loads. This rapid curing also allows the LSM to print in horizontal layers without a supporting structure, meaning we can print walls, floors, ceilings and more.
Other important qualities of the material:
Mobile homes vs Modular
Mighty Buildings is considered a modular home builder which differs from traditional "mobile homes". Mobile homes could serve a means of temporary housing solution whilst our 3D printing technology and unique composite materials are able to bring energy efficient buildings of a high quality and modern design to the market at a cheaper price point than traditional construction.

Modular construction is permanent real property and an appreciating asset. It serves as a long-term investment while mobile and manufactured homes will depreciate in value since they are not affixed to a permanent foundation.

Additionally, financing for modular construction works the same as traditional home or construction loan financing. Mobile homes are financed similar to other depreciating assets like RVs or boats.
Fire resistant
High quality
Appreciating asset
Traditional financing applied
Permanent real property
Long-term investment

Mighty Buildings provides

1 year
Fit & finish warranty on interior finishes
Warranty on structural systems
10 year
10 year Warranty on structural systems
1 year Fit & finish warranty on interior finishes

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