I want to build a small house next to my home, in the northeast behind it, ok?

First of all, it should be emphasized that the Book of Changes is a profound knowledge, which cannot be simply explained and applied by some fixed rules. At the same time, Feng Shui is also a comprehensive subject, and many factors need to be considered to make a reasonable judgment.

According to your description, you want to build a small house in the northeast behind the house. Here are some factors to consider:

1. Geographical location: According to the Book of Changes theory, the northeast position is the "root" position in the Eight Diagrams, representing stability, growth and collection. If you build a house in this direction, you can increase family stability and wealth accumulation. However, it should be noted that this orientation also represents mountains and hills. If there is no such terrain around, other factors need to be considered.

2. Environment: In addition to geographical location, the environment is also a factor to be considered. For example, whether this location is ventilated, whether the lighting is good, the surrounding noise and pollution, and so on. If the environment is not good, we need to consider other locations or take measures to improve the environment.

3. Geomantic layout: In addition to geographical location and environment, geomantic layout is also a factor to be considered. For example, the height, shape, color and so on of this small room need to be considered. If the layout is reasonable, it can increase the happiness and wealth accumulation of families; If the layout is unreasonable, it may bring bad influence to the family.

To sum up, many factors need to be considered to decide whether to build this small house according to the Book of Changes and Feng Shui. If this small house is to be built, it is suggested that a professional feng shui master should be invited to make a detailed survey and make a reasonable judgment according to the specific situation.