When setting cost basis for Home Depreciation, do you also add various improvements made to the house previous to the in home office creation? Exmp. floors, cabinets,roof

[mostaccino]

Since the house was bought I've spent 150k on improvements. For the office itself I have spent 3k to build the room.

[PatriciaV]

Yes, you should include improvements and home-office-specific expenditures when setting up your Home Office Deduction.

Your home and any improvements (that increase its fair market value) are entered separately as Home Office Assets. See screenshot #1 below of the Home Asset Summary page (click to enlarge).

The renovations specific to the home office are also entered as a separate asset (be sure to check the box to indicate this asset is limited to the home office - screenshot #2).

For more help, look for the blue links throughout the Home Office Deduction section.