if section 179 doesn't work the improvements may qualify under section 168 as 15-year property (qualified improvement property - 168 (e)(3)(e)(vii) 15 years is the recovery period for purposes of 168(k)
QIP is defined in 168(e)(6) as
(A)In general
The term “qualified improvement property” means any improvement made by the taxpayer to an interior portion of a building which is nonresidential real property if such improvement is placed in service after the date such building was first placed in service.
(B)Certain improvements not included - Such term shall not include any improvement for which the expenditure is attributable to—
(i)the enlargement of the building,
(ii)any elevator or escalator, or
(iii)the internal structural framework of the building.
under 168(k) property eligible for bonus depreciation
(2)Qualified property - For purposes of this subsection—
(A)In general - The term “qualified property” means property—
(i)
(I) to which this section applies which has a recovery period of 20 years or less,
note that while 179 is limited to business income bonus depreciation is not
