Do i have to give my landlord access to my apt when im not home?

There are repairs that need to be done to the roof (no extreme emergencies) and the roof access is through my apartment but my landlord is insisting on doing the work when i am not home. I am not comfortable having their contractors coming in and out of my apt when i am not there. I have no problem providing access but she is giving me 2 days notice which really doesn't give me time to request time off from work or have someone available to be in the apartment while they are there. She is not giving me a date of completion either, only saying it will take awhile. I want to know if she can actually do this without me or someone else being present. I have expensive things in my apt and i really don't trust her or anyone.