Horror story in construction is called a change order. Expensive. Even if it is a small project. Highly unpleasant. Inevitable if you skip on a detailed scope of work.
This comical example of remodeling a kitchen penciled above is a typical one. When you are dealing with a construction project of a certain scope for the first time, you either find a professional to help you or you learn on the job. Fast.
It is all about scope. At work, when you need to hire any contractor, you start with a technical requirement document or with a design brief. This is what scope of work is in construction. “Make it look nice” just does not cut it.
With ADUs, and with new State Bills that made ADUs a popular way to address the housing shortage, there is one more catch: that consultant, be it an ADU Specialist, designer, builder or architect, has to be familiar with state and local ordinances. Otherwise you will end up wasting a lot of time and/or a lot of money in addition to the usual issues of scope.
I wish those types of stories were true only around Halloween.
And unfortunately, it does not matter whether you are building a custom ADU, or using a modular construction method. There are thousand details, and thus thousand reasons to make a mistake with any construction project.
Become a savvy homeowner, or hire a smart consultant.