The profit on the sale is no longer a capital gain. It's business profit and taxed as ordinary income. In addition you pay self employment tax (social security & medicare). Your fix up expenses are still NOT DEDUCTIBLE until you sell the house. But general business expenses (like mileage) would be deductible. If you sell flip one house and quit; you're an investor. Anything else and it's most likely you're in business, but it depends on all the details.
Again, just "Google" house flipping and taxes. There are plenty of tax expert sites with detailed write-ups on the business vs. investment aspect
