Vastu does not support basements as it creates a hollow beneath our feet. However in modern times they are a necessary evil. Basements should not be built under the entire house. The preferred direction for a basement is East, North or North- East.
The floor of the basement should slope down toward the North East and the walls should be at least 9 feet high.
The basement should not be in the South-West of the building. If at all this is the case it should be used as a storage space only.
Business in a South-West basement never does well and furthur, is downright dangerous and destructive.
A South-east basement can do business of a bar or hotel. The boring or water storage arrangement can be done in the North- East corner.
Since the suns rays do not enter most basements positive energy is not created and it is not at all ideal for either living or for business.
If the suns rays enter the basement between 7am and 10 am then it can be used for business purposes. One can also use a slanting mirror in such a way as to bring suns rays into a basement.
The basement should be painted only white. Blue should not be used.