Client remodeled an attached garage tuning it into an ADU.  

Instead of renting that new ADU, homeowner rented the main portion of the house and moved into the freshly remodeled ADU.    

Can I still depreciate a proportion of the remodel? 

I emphasize they are under one roof, they are not separate buildings.
Rental (main portion house) is 80% of area
Remodeled ADU is 20%.