A year and a half ago I had a crew pour me a 16x26 garage slab as the last part of the renovations I had the cash for. Now I find they poured it without a back to front slope required by code. The inspector says there isn't a specific slope requirement other than any liquid must fall toward the door. I already have walls and rafters framed in. I have 1 1/2 inches at the back to work with to pour something that feathers down to zero in about 24 ft at 16 ft wide. Any ideas that aren't more than starting over?