You really need a geomancer to figure this out, and there are all sorts of feng shui gadgest to help rectify any bad chi in the building. The distinctive roof of Chinese architecture is has a great deal of symbolism involved. Symbolism is present in the colors eave decoration, roofing material, and roof top decorations. A roof usually has a wavy tiling that runs horizontally, and vertical round ridges that run up and down. The vertical ridges are symbolic of bamboo which represents youth and longevity.
Green roofs symbolize bamboo shafts which in turn represent youth and longevity.
This eave and the roof decorations are from the Wong Tai Sin temple complex in Kowloon. From left to right the roof decorations are a dragon, bell underneath, then a man on a chicken, various guardian beasts, and a carp. The carp is an animal that brings success. The more important the building, the more guardians it would have. The number of roof levels also signified the importance of the building.