Step 4: Designing your backyard ADU

Designing a backyard ADU is both hard and fun. Hard – because a lot of costs for an ADU go into very unexciting line items like engineering, foundation or utilities. Fun – because you can make the interior look the way you want – the percentage of the budget that is going into interior finishes that you will end up looking at is typically less than 10%. Were you dreaming of glass tiles in a bathroom? Or black marble as a kitchen countertop? Bright red accent wall? Or just all white interior?

Custom and pre-designed? Depends on the type of your backyard ADU.

Most attached ADUs have to be custom designed. We highly recommend engaging an experienced architect. Ask us for some recommendations if you cannot find any on your own.

Most garage conversions have to be custom designed, though saving money on design here is possible (look for plans that match your garage size). We do have several options in our 200+ ADU floor plan library.

Surprisingly, it is often easier to save money by finding a detached ADU floor plan and adapting it to your backyard and family needs. Check out these backyard ADUs. See anything you like?

Looking to find the right builder for your backyard ADU? Make sure your builder had actually already built ADUs. And not just any ADUs – but the type you are thinking about – attached, detached or conversion. Every type has its own tweaks, and missing a step in planning for them can bring delays during construction.

There is no perfect contractor (who is perfect?), but there is a perfect match.

The construction of backyard ADU is similar to other construction projects and you need to go through all the documentation requirements. Getting your building permit is a necessary expense, and it may cost from $ 15,000 to $30,000+.

Pre-construction phase: from an idea to building permit

Getting your building permit is one of the things you do in your pre-construction phase. 

This is what we typically cover at this phase of the ADU project:

  • Study of feasibility and ordinances
  • Surveying the site
  • Creating the architectural drawings
  • Preparation of the structural calculations and drawings
  • Grading and drainage planning
  • Making energy calculations
  • Paying city fees for obtaining licenses & permits etc

You have to comply with all the state and city requirements to have your backyard ADU permit approved. Make sure you select a professional who knows their ADUs.

Remember, you cannot save money during construction. You can only do it at pre-construction phase. Is your professional motivated to build to budget? Does your professional know the costs to build?

If the phrase above sounds baffling, please talk to us, so we could explain how some early design decisions drive the costs up at construction stage. Your backyard ADU does not need to cost a fortune.

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