Form 8829 – Business Use of Home – Multiple Additions or Improvements
The TaxAct program will automatically create Form 4562 if the date of the improvement entered on Form 8829 is in the current tax year. TaxAct supports only one addition/improvement for Federal Form 8829. If you have more than one addition/improvement, you can still file your return with TaxAct, however you will need to file a paper return (if you print Form 8829, Form 4562 will also print).
See Form 8829 – Entering in Program and How to Mail a Paper Return (Paper File) for details.
Also see the IRS Instructions for Form 8829.