I work as a transcriber on the nights and weekends (1099 work) and have a regular corporate job during the day. My wife and I are expecting another baby and as such, I have to build an office in the basement so the baby can have its own room. My question is whether I can write off the building materials for the office and if so do I have to declare it as an office on my tax return and when I go to sell the house in the future. I live in Illinois.

Thanks for your time.