Whether to build a 3-meter-high fence behind the house depends on the situation. In geomantic omen, the height of the fence should not be too high, because it will depress the gas field of the house and affect the overall gas field of the house and the fortune of the occupants. But if the fence is too high, it may play a certain protective role, such as preventing thieves from entering the house.
Therefore, when deciding whether to build a 3-meter-high fence behind the house, many factors need to be considered, including the view of geomantic omen, the height of the fence, the style of the fence, and the surrounding environment of the house. It is recommended to consult a professional feng shui master or architect to determine the best design scheme.