Section 179 depreciation

land is not depreciable, and a residential and commercial building are not eligible for section 179. certain interior improvements to commercial real estate may qualify

I suggest you read publication 946 starting on page 16 to see what real estate qualifies for 179

https://www.irs.gov/forms-pubs/about-publication-946 

1) 179 won't help if there's a business loss since it cannot produce a business loss.

2) when the property is sold that 179 deduction would be recapture.

3) rental real estate is subject to the passive activity loss (PAL) rules which means the deduction for losses may be limited. The max would be $25,000 with active participation but would be zero if you modified adjusted gross income is $150K ($75K if MFS) or more (before the PAL)