If the design and construction of architectural and residential engineering is completely positioned and implemented in accordance with the model of "innovation or experimentation" and only by sitting in the office and using imagination, the construction industry will enter a dead end and development misunderstanding, and its design and construction works must be immature, and it is very easy to produce sequelae or incurable diseases.
The healthy and sustainable development of the construction industry should adhere to the principles of "development in inheritance" and "large-scale promotion and application in maturity", and must "take the essence and remove the waste", and adhere to the working principle that "practice is the only criterion for testing truth".
Relevant industry authorities or standard setters should attach great importance to the design and construction misunderstandings of "construction industry practices or standards on four types of problems such as exterior wall insulation", and should quickly and pragmatically adjust the current implementation norms and mandatory standards, and cannot build "castles in the sky", otherwise it will be more than worth the loss, but also labor and money.
First, about the exterior wall insulation
1. Analysis of the current situation
Exterior wall insulation is divided into external wall insulation, exterior wall inner insulation, and wall self-insulation, all of which belong to the "wall self-insulation system". The current design and construction adopts a combination insulation system based on "exterior wall outer insulation + lightweight aerated concrete blocks". In any case, the technology is not yet mature, but the status quo is that it has been used in engineering construction on a large scale for more than ten years, which is an abnormal phenomenon.
2. Root diagnosis
Where the exterior wall insulation of the above practices, time will prove: this design result is energy-saving calculation and professional design, in line with the current design specifications and drawing review requirements, although not completely wrong, but certainly unscientific. In the short term, except for leakage, the exterior wall insulation is no problem; In the long run, the consequences are endless. This practice has caused several problems such as "leakage, cracking, falling off, and fire", and the consequences will be more serious in the future, resulting in large-scale falling objects or injuries.
Practice has proved that the wall using the external wall insulation method mainly has two fatal roots: first, the leakage problem; The second is the problem of shedding. This is not entirely caused by construction quality problems, or has nothing to do with construction quality problems at all, but is completely a "belt in the tire" type of congenital problems and seedling pulling and growth problems. With the natural aging of exterior wall insulation products, under the action of temperature stress, acid rain, freeze-thaw and lateral wind pressure, seismic force, etc., the adhesion of the exterior wall insulation wall and the durability of use can not be guaranteed at all, so it can no longer be vigorously promoted and blindly used.
3. Disposal method
The outer thermal insulation or combined thermal insulation system of the exterior wall is a local eccentric force, and the decorative layer of the exterior finish is a non-axial force, which is an external adhesion.
(1) For the formulation of wall insulation indicators, the requirements for energy-saving design indicators are too high, and the specifications and strong standard requirements should be reduced or not required, and the threshold restriction should be removed, otherwise it is "better than no book".
(2) The exterior wall can be replaced by the design of "three seven walls" or "four nine walls" and "double windows", and the design is carried out according to the axial force of the beam, that is, the external wall construction does not fly out of the beam, and the external wall load-bearing beam, foundation and pile can be built and designed together. The use of this kind of wall in the north has proved to be a successful case, and it is more conducive to seismic resistance, impermeability, grooving and structural safety of the building, which is a matter of time and for all, so it should be worth vigorously promoted.
(3) The exterior wall adopts soil sintered bricks, does not use light aerated concrete blocks, etc., and the source of soil can use soil excavated from basements, civil air defense and other projects or dredging from rivers, which is conducive to all kinds of fixed and secondary structure construction and avoiding leakage.
(4) Cancel the energy-saving index of beam and column cold bridge, and consider the design of special nodes of the cold bridge; Second, the design size of the beam width can be increased, which is only used to increase the outer protective layer of the beam to avoid the occurrence of exposed ribs on the outside of the beam.
(5) To cancel the practice of exterior wall insulation, the painting process of hanging glass fiber mesh cloth can be directly adopted to ensure the integrity of the stucco layer and the self-shrinkage of the building materials.
(6) The exterior wall can be indented 2 cm to the inside of the beam to ensure that the finished product of the stucco layer at the upper mouth of the beam is level with the outer side of the beam, and the lower three skins at this place are constructed using standard clay brick masonry or 200-high C20 plain concrete water-stop sills, and a horizontal "parallelogram eagle's beak plastic grid line" is designed at the junction of the upper mouth of the surrounding beam and the rear masonry wall on the outer side of each floor, and then the exterior wall real stone paint process or other finishing processes or other processes are carried out. The advantage of this is that the same layer bears the adhesion of the stucco layer and counteracts the temperature stress.
2. About "solar energy"
1. Analysis of the current situation
Solar energy is clean energy, which should be vigorously promoted, but it cannot be one-size-fits-all, and should be adapted to local conditions and events. It is often found that the phenomenon of "panel solar energy" using one wall for new high-rise and small high-rise houses is more common, the water tank is installed on the balcony, and the solar panels are hung on the outside of the sealing beam of the south balcony, obviously only to pass the drawing review and various acceptances, but lack the practicality and humanization of the design.
2. Root diagnosis
(1) Install solar panels on the balcony on the south side of the exterior wall, brackets and other metal components will rust, and it is easy to cause solar panels and brackets to fall off with the passage of age, resulting in falling objects from height. The quality warranty period of the product is usually only two years, if the maintenance is not carried out in time in the later stage, there are potential safety hazards or safety accidents that hurt people from falling objects.
(2) The solar water tank occupies the indoor space of the balcony, which is extremely impractical, so the demolition rate of the solar water tank reaches 100%, and it is basically replaced by a gas water heater during the decoration, and there is a serious waste of resources and products, which should attract our great attention.
(3) The installation method of this kind of wall "panel solar", if the lightning protection grounding is not in place, it is prone to lightning or electric shock accidents. However, in the actual process of viewing the house, in the use of wall "panel solar", I did not find its related lightning protection supporting devices, which is more common and indeed worrying.
3. Disposal method
Option 1: Reduction system. The operation experience of the automotive industry tells us that there are standard equipment, top equipment, etc., and can also be tailored according to customer requirements, the design is very mature, we can learn from it, why not? Similarly, the solar energy of "super high-rise, high-rise and small high-rise top six floors", "multi-storey and villa whole building", can be designed at the roof bracket or frame to install solar panels or solar tubes, other floors or buildings do not have mandatory requirements for solar energy installation indicators, and can be achieved by each user installing gas water heaters.
Option 2: Start from scratch. To do "useful" and "permanent", change the installation location of the solar energy of this balcony, you can set the solar panel and the water tank together like the "box shelf room" in the installation position of the outdoor unit of the air conditioner, or adopt a conjoined design, one receives sunlight "outside", the other "inside" water source replenishment, and sets an equipotential terminal box connection point at the inner wall of the shelf room as a lightning protection facility for solar energy connection. Only in this way can the outdoor hidden installation of ultra-high-rise, high-rise and small-high-rise panel solar energy on the same floor be realized.
Disadvantages: (1) The single balcony can basically realize the second practice, but the double balcony is difficult to achieve, and to pass the solar water supply pipeline in the ceiling of the room, the pipeline needs to be insulated and silenced; (2) Sun plate ash accumulation and impurities in the water tank are not easy to clean; (3) Solar energy equipment should be designed with corresponding matching fixed size products with structure and building synchronization system; (4) Increase the difficulty of solar after-sales and maintenance in the future; (5) It is suitable for housing with large apartment type, and is not suitable for housing with small user type, which has limitations; (6) If the housing with a small unit type is mandatory according to its practice, the façade of the wall is extremely unsightly, and will affect natural ventilation or lighting; (7) The water output of hot water in winter cannot meet the normal use, and other water heaters need to be used for assistance.
Advantages: (1) It is a renewable clean energy, which greatly saves energy, conforms to and actively responds to the national carbon neutrality policy, and is worthy of praise and promotion; (2) Reduced cost of living, economical and practical; (3) Does not occupy indoor use space, easy to decorate, beautiful and generous; (4) It can be installed synchronously with the civil engineering.
Solution 3: Set up the solar equipment layer. A whole layer of solar equipment can be designed every 5~6 layers, the exterior wall surface is used to install solar curtain wall collectors, and the water tank is installed in its equipment layer, and the layer can take into account other uses of the equipment layer.
Disadvantages: (1) large one-time investment; (2) Solar plate ash accumulation is not easy to clean; (3) Other shortcomings, some of which are the same as plan 2.
Advantages: (1) the same scheme two; (2) Easy to repair and maintain.
Solution 4: Solar centralized hot water supply. Solar panels or curtain wall collectors can be centrally installed in the "roof" or "exterior wall" or "roof + exterior wall" parts, and the installation process of curtain wall collector panels can adopt a similar process of "dry hanging of exterior wall stone construction", and the water tank can be installed on the roof. According to the principle of "instant heating" to design the solar water system, each vertical main hot water supply pipe should be designed with a return water lifting pump, and a hot water meter with remote water is installed at the hot water outlet of each household between the floor water meters, and the hot water docking branch pipe is connected after the meter.
At the same time, it should be clarified: the water company will implement the collection of water bills and the daily maintenance and repair of the solar system; Installation can be carried out by the developer, and the water company is responsible for acceptance and operation. Otherwise, such an option is not desirable. In order to facilitate the cleaning of the water tank, double water tanks can be designed, one for use. The vertical pipeline of this scheme can be optimized between the public staircase and the water meter, and the plane size between the water meter can be appropriately increased considering the installation and maintenance size.
Disadvantages: (1) high installation technology requirements; (2) The ash accumulation of the solar panel on the exterior wall needs to be cleaned and maintained and repaired by professionals regularly; (3) If the water supply main or supporting equipment is damaged, the phenomenon of centralized stopping of heat supply will occur; (4) The lifting pump should be two in one circuit, according to the "one backup and one use" design, and the roof needs to be designed with a multi-layer structure or occupy the roof space to affect the roof leakage maintenance; (5) The public energy consumption fee of the return pump is difficult to collect in the later stage, so the water company needs to collect it uniformly in the water fee; (6) Part is the same as option 2.
Advantages: (1) The exterior wall is more energy-saving and insulated; (2) It can prevent and reduce the occurrence of external wall leakage; (3) It has little to do with the interior decoration plan and is easy to use; (4) Other advantages, the same as scheme two.
To sum up: option one is "the simplest"; Option II "most applicable"; Option 3 is "most expensive"; The fourth plan is "the most energy-saving" and "the most technical", but the public electricity consumption and equipment damage repair need the state to issue policies, in the name of water fees, let the water company unified reception and management.
Third, about the waste of wires and sockets
1. Analysis of the current situation
The most basic conditions for the acceptance of residential projects should be water, electricity, and the lights in each function room should be on. Resulting in waste of resources. If it is a well-decorated room, water and electricity can be synchronized with the decoration, which is no problem. If it is a rough room, the originally designed lights, socket lines and related waterways will basically not be used, and there is a high probability of being demolished, and even if it is used, it is temporarily used in the early stage of decoration, and the use value is not large, so there is a serious waste of resources.
2. Root diagnosis
"Waste is a crime, and saving is in accordance with nature." Practice has proved that man-made restrictions in design, drawing review, acceptance, etc., are the source of direct waste of wires, sockets, etc., and are extremely irresponsible for social and earth resources. According to incomplete statistics, the utilization rate of simple lamps and sockets in the original rough room after renovation is less than 3%, and the removal and replacement rate is extremely high.
The main reasons: First, the grade of the above products in this article is not enough; Second, the location of its design does not meet the adjustment requirements of later decoration; Third, the color and function of the product do not match the decoration requirements in the later stage. Therefore, the indoor wires and sockets of the current rough room should be designed to be reduced, and the specifications of design, drawing review and acceptance should be clearly stipulated: only the access point or junction box of strong and weak electricity provided in the residential room can be canceled. This can avoid the serious waste of resources, do not repeat the grooving in advance, ensure the integrity of the wall, and reduce the probability of cracks in the indoor wall and the occurrence of empty drum phenomenon.
3. Disposal method
Arrange access points in suitable locations, such as: one strong and weak electrical junction box; The bathroom, balcony, and kitchen are each equipped with an equipotential terminal box. The strong electric box should leave enough empty open circuit and backup circuit, the wire diameter of the incoming line should be larger, the power load should leave a margin, the size of the electric box should be larger, it should be convenient for future upgrades, adjustments or replacements, and the outlet line should be taken care of by the user.
4. About flue and toilet exhaust duct
1. Analysis of the current situation
Residential construction, design works from the design institute, all designed kitchen flues and bathroom exhaust ducts. Practice has proved that the flue and exhaust duct do play a certain role in actual use, but the effect is unsatisfactory. In the actual use process, even if the check valve is added at the flue and exhaust port, there is indeed smoke return and air return phenomenon.
2. Root diagnosis
(1) Occupy a lot of space; (2) The decoration effect is not good, and there are convex sunny corners; (3) The flue pipe on the floor is easy to leak; (4) There is a phenomenon of "smoke return, gas return"; (5) The phenomenon of "oil accumulation and water alkali" in the flue on the first floor, and oil accumulation in the first layer flue, there is a fire hazard, and it is easy to string fire up and down the floor.
3. Disposal method
Directly reserve stainless steel casing or outlet pipe on the exterior wall beam of the kitchen room or bathroom, and during the construction of the outer wall undercarriage, and then install the "rainproof, bird-proof, bat-proof, insect-proof" four-proof stainless steel mesh shield at the casing or outlet pipe, and the shield can be the same color as the exterior wall.
The analysis and diagnosis of the above four aspects may have inappropriate insights, and further improvement is needed in the future. To cure the above problems, multiple design units can be organized to re-issue the corresponding standard drawings or construction nodes, but they must be discussed and recognized by multiple experienced construction parties before promotion.
Source: Building Technology Magazine Design
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