If the improvement was for the entire home you enter it as for the entire home and the deduction would be calculated based on the business use percentage. Here is a link with some helpful steps.
Next, you will need to divide the space percentage between the two businesses. The IRS does not specify an exact procedure, it just needs to be reasonable. There are several ways to accomplish this. Here is another helpful link to give you some options.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
