Is work being done to improve or add on to the property while it is idle? Here's what the reg says can be capitalized.
The items thus chargeable to capital account are:
(i) In the case of unimproved and unproductive real property: Annual taxes, interest on a mortgage, and other carrying charges. [this is not applicable to you].
(ii) In the case of real property, whether improved or unimproved and whether productive or unproductive:
(a) Interest on a loan (but not theoretical interest of a taxpayer using his own funds),
(b) Taxes of the owner of such real property measured by compensation paid to his employees,
(c) Taxes of such owner imposed on the purchase of materials, or on the storage, use, or other consumption of materials, and
(d) Other necessary expenditures,
paid or incurred for the development of the real property or for the construction of an improvement or additional improvement to such real property, up to the time the development or construction work has been completed.
You may have nothing to capitalize.