Commercial /Residential depreciation do I need a 3115?

[michele]

I really should be able to do these 3115 in my sleep by now!!!  This couple owns a commercial property I have been depreciating as 39 year property.  They have now started renting the property upstairs to an individual to live in as a residence. The lower is staying as commercial. Since I am changing  to 40% residential and  60 % commercial do I have to do a 3115?  

thanks

Michele

[TaxGuyBill]

Unless 80% of the rent is residential, the entire building remains at 39 years.

[michele]

Thanks I was going to look up the regs. I had not had anyone use commercial as dual.

[BobKamman]

Learn something every day.  Sec. 168(e)(2) .