With the development of the country’s economic construction and the gradual improvement of people’s living standards, improving the living environment, beautifying the urban landscape, and improving urban tastes have been put on the agenda of government agencies at all levels. According to the survey data of the relevant departments and our investigation of the original housing of the new steel company, the leakage rate of the roofs of existing residential buildings (especially prefabricated hollow slab roofs) is as high as 80. This article presents the status quo and remodeling of the flat roofs of Xingang Steel and even Xinyu City. Method to do a discussion.

1 Status Quo of Residential Flat Roofing In the 1980s and 1990s, Xin Steel Company built a large number of multi-storey dwellings, with 5 and 6 floors in the early stage and 6 and 7 floors in the latter stage. Most of the dwellings were limited to economic conditions, and most of the roofs were pre-built. A flexible waterproof layer is arranged on the stress hollow plate, and a reinforced concrete insulation board is laid on top, or a waterproof layer of linoleum or felt, and then a perlite insulation layer is spread. Due to improper design and construction, waterproof materials, and improper management, the roof leakage problem is more common and the insulation and insulation effect is not good enough, causing worries to the residents.

Residents have their own needs, some build a variety of antennas, and some build illegal construction such as pigeon cages and small penthouses. What's more, they use the roof as a warehouse, garbage storage, and disorder, seriously affecting the appearance of the city. As a building, its roof is an integral part of its entirety. Whether its design is beautiful or not, and whether it is handled properly, is important for the overall beauty of the building. In view of the above situation, in order to ensure the normal use, safety and beauty of buildings, it is necessary to renovate the original flat roofs of houses, not only to change the dirty, disordered, and poor roofs, but also to add a clean and beautiful appearance to the urban environment. Completely solve the leakage, insulation, heat insulation and other issues of the house.

2 Several current practices (1) The construction of asbestos tiles or glass fiber reinforced plastic tiles on the existing roof has many disadvantages. It is inconsistent with the original style of the building, is inconsistent, and has poor durability and should not be used.

(2) A cast-in-place reinforced concrete insulation layer shall be installed on the erected brick column. This kind of Jiangxi metallurgical method is used more often. The disadvantage is that it seriously affects the appearance of the building. In the construction process, the construction process of the brick column and the original soft felt layer cannot be dealt with, leaving the trouble for re-seepage. In order to save investment, the thickness of cast-in-place slabs is often designed to be too thin, so cracks are found after completion. Therefore, this method should be used in small quantities. The cost of this method is about 120 yuan/m3. The structure of residential buildings is analyzed from the structure of residential houses. Most of them are brick-concrete dwellings, some of which have bottom frame houses and pile foundation houses. They are built with no earthquake protection and are surrounded by beams. The early stage is generally Mu 75 bricks, bottom 2 layers of M 5.00 mixed mortar, more than M 5.2 mixed mortar, and late 1 and 2 layers of structural columns. The bottom bricks are marked with M u10 and the mortar reaches M10.

4 Methods and Measures for Renovation Because the existing building has different conditions, the following problems must be considered in the reconstruction of flat roofs: (1) Drawings on the completion of existing buildings (2) Geological survey data (3) Status of houses Situation (4) Owner’s economic situation and intention. According to the collected data, the calculations and calculations mainly include the bearing capacity of the roof, walls, bricks, and foundations. If the recalculation does not meet the regulatory requirements, it must use appropriate reinforcement measures.

There are two ways to retrofit old flat roofs: one is still a flat roof, suitable for maintaining the original building environment and maintaining its own architectural style, the other is a flat roof with a sloping roof, and the slope roof has a comparative advantage in the southern region. Large advantages, smooth drainage, good thermal insulation and ventilation, greatly enrich the appearance of the building. At present, large and medium-sized cities in the south are widely used, and we recommend that they be promoted and used where economically viable.

4.1 Durability Waterproof and heat insulation methods This method can preserve the original architectural style, and the construction is simple and economical. Its roof structure is composed of five parts: water-collecting cover plate, hydrophobic minor groove, diversion big groove, trench joint and venting brick. Using modern building techniques to build waterproof and heat-insulating roofs (Figure 1). Because the roof is constructed of a hydrophobic diversion and waterproof structure (Fig. 2), it forms a continuous heat-insulating ventilation layer with the ventilation bricks below the parapet wall (Fig. 3). Its characteristics are: (1) Waterproof performance is good. Because of its good waterproof performance and its own structural characteristics, even if uneven building sinks, temperature changes and other environmental differences, will not change the fastening state of the cover plate and the size of the ditch, not It will affect the overall waterproof effect of the roof.

(2) The service life is synchronized with the building.

(3) The heat insulation performance is good, because the heat insulation space under the cover plate is communicated with the ambient air via the ventilated tundish, so the best effect of ventilation and heat insulation can be obtained.

(4) It is easy to maintain.

(5) Construction is convenient and pollution is eliminated. The cost of this method is RMB 80/m. 4.2 The method of changing the flat roof into a sloping roof is to enrich the urban landscape. According to the different forms of house facade treatment and material practices, we can make the roof a double slope, four slopes, and partial slopes. According to local conditions, treat differently, so that the transformed buildings have their own characteristics. Considering the requirements of planning and other aspects, the height of the slope top is generally controlled at about 2 m. Under the condition that the load is allowed, if the ventilation and lighting of the house are not affected, compensation may be considered.

4.2.1 Color steel tile roofing practices are colored profiled steel tile (color can be selected according to the original building requirements), channel steel or profiled steel, original roofing. Its characteristics are lightweight, high-strength, earthquake-resistant and wind-proof, simple construction, beautiful and durable, and long service life. In the case of the base load allows, each partition wall to the required height, generally about 2 m, and then the finished channel steel or steel and ring beam fixed, and then the color steel plate with screws fixed to the steel.

Its cost is about 150 yuan/m. 2. It is suitable for roofs with less slopes. Because the slope is too large, snow falls easily when the snow falls, and it is easy to cause damage.

4.2.2 Machine flat tile wooden roofing 400 water-strip, oil felt layer, 20 mm thick fir roofing board, Υ140 1 200 fir slats. This method is characterized by convenient construction and low cost, about 120 yuan/m 4.2.3 The practice of reinforced concrete roof is machine flat tile (or red brick, etc.), 25×25 wailing tile 36×8 600 water-strip, waterproof roll Material, 20 thick 1:2 .5 cement mortar leveling, cast-in-place reinforced concrete roofing panels (double reinforcement in the board), plus a ring beam at the bottom to increase the overall stiffness of the house. This approach is characterized by a good overall structural rigidity After solving the problem of vertical traffic between the top floor and the top of the slope, it can increase the area of ​​use of the top tenants by 30 to 50. For those households with small original housing areas, it is certainly welcome, so we recommend that The construction management department and the households jointly contributed funds. The method of households using Xiaopolou: that is, increase the source of funds, alleviate the problems of residential housing, and achieve a double harvest of social environmental benefits and economic benefits.

To sum up, in order to solve the legacy problems of the original residences, the architects can design different personalized slope roofs according to the different characteristics of the environment and the actual conditions of the residential areas through the changes in the roof form and the color changes. The urban landscape is more colorful and more charming.

(English translation Lu Hong) Jiangxi Metallurgy August 2001

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