Chapter VII of China's Property Law makes specific provisions on neighboring relations, among which Article 84 stipulates: "The neighboring obligee of real estate shall correctly handle neighboring relations according to the principles of favorable production, convenient life, solidarity and mutual assistance, fairness and reasonableness." Article 89: "The construction of a building shall not violate the relevant national engineering construction standards, and shall not interfere with the ventilation, lighting and sunshine of adjacent buildings." Article 90: "Property owners shall not abandon solid waste and discharge harmful substances such as air pollutants, water pollutants, noise, light and electromagnetic wave radiation in violation of state regulations." Article 91: "A real estate owner may not dig a hole to borrow soil, build a building, lay pipelines or install equipment, which will endanger the safety of adjacent real estate." Article 92: "Property users use adjacent properties for water use, drainage, traffic, pipeline laying, etc.". We should try our best to avoid causing damage to neighboring real estate owners; If damage is caused, compensation shall be made. " In addition, China's property law also has provisions on the protection of property rights. Article 35: "If the real right is damaged or may be damaged, the obligee may request to remove the obstruction or danger." Article 36: "If a realty or chattel is damaged, the obligee may request to repair, redo, replace or restore it to its original state. Article 37: "If the infringement of property rights causes damage to the obligee, the obligee may demand compensation for the loss or bear other civil liabilities. "
In addition, regarding the statement that "Gai Lou is not allowed within a few meters of our house according to the law", it is certain that there are gaps between houses, and the state should also have regulations. You can check the Code for Planning and Design of Urban Residential Areas, which is the national standard of People's Republic of China (PRC). I looked at it. It was too professional to understand. You can also go to the website of the local urban and rural planning bureau to see if there are any relevant policies.
All the above laws apply to the situation you are facing. You can claim to remove the obstruction and compensate for the loss, but the key is the evidence. You'd better take photos yourself now for future litigation.