Judging from the effect after completion, it has achieved the expected social and economic benefits. 1, 30 houses are acquired without land acquisition. Shiyan mountain area has less land and more mountains. Using one piece of land, losing one piece, and not occupying land can also increase the housing area. This is the greatest social and economic benefits. It is a feasible and better way to carry out reconstruction construction without moving residents, which makes the factory, employees and housing management departments satisfied. 2. Adding stories to residential buildings can save a lot of site development costs, such as earthwork costs, urban residents' relocation costs, road flood control costs, etc. 3. The storey-adding renovation of residential buildings should strive to achieve the best effect, and the storey-adding renovation of residential buildings or civil buildings below 4 floors should be increased to 7 or 8 floors at one time, so that the bearing capacity of rock-socketed digging piles can be fully utilized and the cost of storey-adding per unit area can be reduced; But it should not exceed 8 floors, because 8 floors are the dividing line between high-rise buildings and multi-storey buildings. If you want to install elevators above the eighth floor, the cost will increase greatly to meet many special provisions of the high-rise design code, which is not desirable. Increasing to 8 floors is the best solution. Multi-storey residential buildings with more than 5 floors should not be retrofitted, unless they are treated as high-rise buildings. 4. In the story-adding design, schemes should be compared and a reasonable structural scheme should be selected. The outer frame method is not the only solution. If the number of stories added is small, the bearing capacity of the original design wall and foundation is large, and the story-adding reconstruction can also be directly carried out according to the original structural system. 5. In the design of storey-adding renovation of old houses, we should consider the building facade as much as possible, especially the buildings facing the street and public buildings. The traces of adding stories should be erased, so as to look brand-new, beautify the city and update the environment. 6. The external frame scheme adopted in the renovation of old houses must be combined with seismic design. When the old house is on the third or fourth floor, the columns at the bottom of the frame are very high. If there is no transverse wall to form a combined structure, it will not be conducive to resisting the effect of transverse flowers and earthquake resistance, forming a practical "separated" structure, which will make the column section too large and cause waste; "Integral" scheme should be adopted, such as the connection between the outer frame and the transverse wall of this project, and effective connection should be ensured in design and construction. Xi' an reinforcement reminds people to choose a good reinforcement technology website.