I am Self Employed and built a new studio on my parents property, it is exclusively for my business and is separate from the house. Where do I enter this expense?

It would be similar to renovating my work space, but is a new space. I have not used the usual home office deduction as my parents have allowed me to use the space for free, but I did pay to build my new studio outside the house on my own. I would like to deduct this from my business expenses.