You don't write it off per-se. It's a property improvement that has to be capitalized and depreciated over time. That time would be 27.5 years in your case. You'll enter it is the Assets/Deprecation section when you get to it.
Property Improvement.
Property improvements
are expenses you incur that add value to the property. Expenses for this are
entered in the Assets/Depreciation section and depreciated over time. Property
improvements can be done at any time after your initial purchase of the
property. It does not matter if it was your residence or a rental at the time
of the improvement. It still adds value to the property.
To be classified as a
property improvement, two criteria must be met:
1) The improvement
must become "a material part of" the property. For example,
remodeling the bathroom, new cabinets or appliances in the kitchen. New carpet.
Replacing that old Central Air unit.
2) The improvement
must add "real" value to the property. In other words, when the property is appraised by a qualified,
certified, licensed property appraiser, he will appraise it at a higher value,
than he would have without the improvements.
