Split an existing home or add an ADU?

[Angela Zaitz]

I'm considering either splitting a 3 bedroom home or 2 bedroom with den or bonus room. I had one with the perfect layout with large bonus room that would have been perfect but there was mold, termites and major wood rot so I backed out.  It is a coastal area in San Diego  and the homes that are in my price range are all older and more  prone to mold. I've had health issues related to mold and would like to avoid this since I would be living in one of the units. If the water damage isn't recent and drywall was replaced or stain painted over and not disclosed, I don't think a home inspector would be always able to tell, or?

My other option is to buy a home with a larger yard and add an ADU (live in ADU and rent main house. I think a prefab would be easier and cheaper then a stick built add on in general, or?

Any input? Any experience with doing splits or using ADU's ? reasonable brands?

I am willing to live on site in  a 1 bedroom or roomy studio, but not willing to have traditional roommates.

This will be my first investment home I will purchase and would appreciate your expertise. Thanks!