In Crested Butte, basements are a way to gain more living space, especially given the tight zoning in town. Basement square footage for the most part isn't counted in the limited square footage allowed in town. However, it has gotten really expensive to build a basement due to new rules that don't allow sump pumps. The new building of basements requires building what is equivalent to a boat that floats on the water table so the basement doesn't need to be pumped out with the spring runoff. These basements are terribly expensive though, and can add seriously to construction costs. Make sure to get a builder to estimate these costs before committing to buying on lot if you need the extra square footage.