Real Estate Articles

How to Build an ADU/Granny Flat | By: John Arendsen

Granny flat? Backyard Home? Garage Apartment? Pool Cabana? 

Would you like to find a property that already has an Accessory Dwelling Unit (ADU) aka BACKYARD HOME on it? Or are  you looking for a property you could build one on?


Since the new State Laws were enacted in January, 2017 the BACKYARD HOME industry has gone from a cottage industry (pun intended) to a major growth industry. Property/homeowners, buyers, sellers, real estate professionals investors and myriad industry stakeholders are clamoring to find experienced professionals to deliver all the services needed to facilitate the purchase of a suitable property; Then be able to design, build and or install it. 
There are so many hoops to jump through it becomes a time consuming if not overwhelming, frustrating often very unpleasant experience for many folks
going down this path. Here's why. First you must:
  • Find an experienced Real Estate Professional to locate a suitable property that meets the necessary criteria for an ADU or JADU.
  • Or find a suitable property that already has a detached Accessory Dwelling Unit (ADU) on it.
  • Or a Junior Accessory Dwelling Unit (JADU) already built out within the existing footprint of the primary residence.
  • Or add additional contiguous space onto the existing footprint of the primary residence. 
  • Or if an ADU or JADU already exists you need to determine if it was ever permitted and if not how many hoops you will have to jump through and how much it will cost to make it a legal, conforming and code compliant addition to your property.
  • Find a property/s that meets both your criteria and the required criteria to design and build your BACKYARD HOME.
  • Have a survey performed to assure not assume the property boundaries, setbacks, easements and encroachments.
  • Hire a soils engineer to determine geological suitability and site prep requirements.
  • Hire a civil engineer to determine design criteria.
  • Hire a structural engineer to calc out and verify design criteria.
OK, so now you've found and purchased the dirt. What's next? 
  • You need to commission an architect to design your BACKYARD HOME or
  • Hire a design/build contractor to design and build it. (Recommended) or
  • Choose a factory built solution and manufactured home dealer and contractor. (Highly recommended for a variety of reasons).
So now after several weeks if not months you've finally have a plan and are ready to proceed to the permit counter.

 Here come the real challenges:

  • Selecting a properly licensed, bonded, insured and experienced BACKYARD HOME general contractor or
  • have already hired a design and build contractor to design, build and manage the entire project. 

 Your design should include a

  1. Full set plans & specifications including working drawings
  2. Plot plan: You can obtain one from your local building department or the County in which the property/home is located. Or your architect or design/builder will obtain it for you once you have retained them. The plot plan should delineate your boundaries, setbacks and easements. However, do not always count on their accuracy. Fences are not always your best friend and plot plans seldom record encroachments. Thus a complete property survey is highly recommended.
  1. Plan view (Below)
The plan view should look like the drawing above be it a ground up site built or offsite factory built. It will delineate your interior floor space with dimensions, door openings and windows.
  1. Elevations (Below)
Elevations will include all four views, front, rear and both sides of the exterior structural elements of the home. It will define the components and materials the structure is composed of be it a ground up site built or offsite factory built structure.
  1. Details 
  2. Shop drawings when required
  3. Notes
  4. Addendum
  5. Change orders
Or have selected and submitted your plans for a factory built option that will allow you to have the entire home built in an environmentally controlled indoor manufacturing facility with kiln dried lumber and state-of-the-art building materials, features, options and upgrades.  
Finally comes the most important phase of the project. This is where it can get a bit challenging. Folks can become very surprised if not discouraged by not having all their ducks in a row. These are the hoops you will now need to jump threw and the costs that can make you a happy BACKYARD HOME owner or not and your contractor a success or failure. 
  • Permits
  • Site preparation
  • Grading & excavation
  • Utilities
  • Retrofitting
  • Construction
  • Management
  • Payment
Most importantly be sure your contractor has had ample experience plunking down a new structure in the middle of a bunch of existing utilities that are connected to your existing
home and have to be trenched and connected to your BACKYARD HOME.
Depending on the age of the property they could be old and in need of repair, replacement and/or upgrading:
  • Water
  • Gas
  • Sewer
  • Power
These utilities, depending on the age of the existing utility grid, could be close to or if not in a state of disrepair and/or in need of a drastic retrofit and upgrading face lift. This can and has been a catastrophic experience for many property/homeowners as well as their contractors. It can, will and does make or brake a project.

 Finally, you may even want to consider going:

  • Off grid design
  • Green & Leeds compliant
We invite you to download our CREST 'BACKYARD' HOME GUIDE. This easy to read 8 step GUIDE will walk you through every step you need and could save you hundreds if not thousands of dollars in needless consulting and contractor fees.

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