Garage conversion into an ADU

[Andrew B.]

Hello everyone! 

We are trying to convert a detached garage into an ADU. I went to the city and they said that I can do it and even add square footage. We have the space to add additional square footage but that would mean that I would be taking over some of tenants current backyard space. Our property is a duplex in National City CA. The current houses are detached and the garage sits in the middle with room to expand towards the front and the sides. Both of my tenants are month to month now. We are trying to do this ASAP. They each have a back yard they would still home some yard left even if we add the extra space. My question is can I do this while they are still living in the property? or do I have to wait until they move out in order to start construction? We are still in the planning stages since we are looking for a draftsman or a reasonably priced architect. If you have any recommendations please let me know. Thank you for all your help!