Several factors influence the cost of finishing a basement. Most prominent factors are custom services, artisan features, brand, quality, material and area. Other factors that influence cost are foundation type, preparation needed, location of water heater, furnace, plumbing, HVAC and electrical systems and the need for relocation or adjustment based on the height and design of the ceiling. On an average level, it can be said that the cost per square foot varies between $ 40 and $70.