Please consult with a tax expert before doing this. Two things come to mind: this kind of deduction can raise a red flag and trigger an audit. The second is that you need to make sure that when you sell the property that this doesn't come back and bite you. Selling your primary residence is tax free, but when you deduct part of the property as business then that part may not be classified the same.
Be careful: make sure the reward is worth the risks and costs long term. Consult a skilled tax consultant.