As stated previously moving the locations of the existing fixtures increases the cost of the project. Renovations that require moving the existing walls requires additional costs. Building new additional space to the existing house footprint requires all the rudiments of an addition. excavating, grading. Footing,draining, slabs, foundation and the full gamut of construction with framing. Installation, plumbing, electrical, windows, doors, and extreme roofing and siding. Obviously the cost grows substantially with an addition. A budget discussion in the initial meeting will create the bounds of the project. Always allow a slush fund, setting aside an x amount of money for inevitable hidden unforeseen extras that need to be addressed. A contractor has no idea of the flaws found in the residence, until the walls are opened as well as the ceiling and especially the floors. Most often either rot or structural problems are found, or mistakes left by the original construction crew, or even fixture or installation leaks. All flaws have to be addressed. Unlevel, unplumed out of square surfaces have to be replaced.