Garage Conversion into ADU... tenants' stuff in my garage

[Cathy S.]

I am planning to start construction on my garage ADU next month (already pushed back many times due to Covid, getting permit issued, among other things). I have told my tenants that I was planning on converting the garage since February, and kept on updating them over the last few months that yes the conversion is indeed happening, this is the date to expect it to start etc.

Due to their own personal circumstances, they brought an elderly parent over to the rental unit, along with a bunch of stuff that they are storing in one of my garages (that I will be converting). All of their stuff takes up almost the entire 10x20 (single car garage). I am trying to work with them to find the best solution. The best I can do is having a custom shed installed (something about 6'x12'x6') out in the front yard (is this even being too generous? This is another cost of about 3k out of pocket to accomodate these tenants). However, the shed guy won't be able to start until the same day as the start date of the garage conversion. Another thing to note is there is no mention of using the garage in their lease (I inherited these tenants and they had already been using the garage with the previous owner, and when they renewed with me, my lease didn't state anything about using a garage).

What I can do (but don't want to do) is to delay my project AGAIN by having my construction guys come by a week later after the shed is built, to give the tenants time to move their stuff (will the shed fit all of their stuff? I don't know). I have let them know a few days ago with the hard dates, explicitly stating that both garages need to be empty by November 4 because construction can't start until everything is out. 

My question is.. what if they drag their feet and don't actually get all their junk out by the start of construction? Of course I will keep on reminding them weekly to get them moving. But is this something that I need to start consulting with an attorney about ? (worst case scenario, they don't move their junk).