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(One Hundred Questions on Waterproofing) The ceiling of the #86th-floor elevator room has experienced a leak phenomenon; given that it is above a water tank, what are the key aspects of the concept that should be considered when repairing the leak?

A: Generally, if the ceiling of the elevator room in the top floor of a residential building experiences a leak, because the water storage tank is located above it, the first thought is that it is probably caused by a water tank leak; however, it must be noted that the water tank is located in the basement of the building.

(One Hundred Questions on Waterproofing) Which series of waterproof materials should be used for the water storage tank in a #85new construction site? What are the standard construction specifications?

A: According to the waterproofing standards of the Japan National Association of Architects JASS No. 8, it is recommended to use water-based and solid-state waterproofing materials (categorized into acrylic resin series and EVA).

(One hundred questions on waterproofing) What is the most common mistake in the construction process when waterproofing a #84new construction site pond? Is it suitable to use PU, EPOXY or FRP construction?

Answer: (i) In the process of waterproofing the tank, the most common mistake made on construction sites is to first paint the base and then apply the waterproofing coating. The reason is that since tanks are generally prone to leakage, it is necessary to first seal the base before applying the coating.

(One Hundred Questions on Waterproofing) #83: In some cases, the waterproof coating is only applied by brushing with seven-millimeter quartz powder or by buying some waterproof agent at a hardware store; there is no leakage phenomenon. On the other hand, some construction sites use expensive imported materials from Europe and the United States, but they often leak, and repeated repairs are ineffective. Why is that?

Answer: The key lies in the structure of the tank; as in question 83, ninety percent of the water leakage is due to four major defects in the structure; if these defects are properly addressed, a simple 1:2 countermeasure can be applied.

(One Hundred Questions on Waterproofing) #82: What parts of ordinary storage tanks are prone to leakage? What are the two main methods for constructing the tank structure? Which method is less likely to cause leakage?

Answer: (i) The common areas prone to water leakage in reservoirs are: (ii) Construction methods include U-shaped and M-shaped structures. The U-shaped construction method is because the bottom and the wall are integrated into one unit.

(One Hundred Questions on Waterproofing) #81: How does waterproofing in bathrooms and toilets in newly constructed construction sites work? If (a) polyurethane (PU) is used, what is its functional performance? After construction, there is often a phenomenon of residual adhesion (not fully cured); how can this be prevented? (b) Rubberized asphalt (RA) is used; what are its advantages and disadvantages? (One Hundred Questions on Waterproofing) #81

Answer: (i) If PU construction is adopted, the waterproof performance of the RC wall remains acceptable; the only drawback is that it cannot be painted or primed; however, for the brickwork part, it is very difficult to completely seal the surface.

(One hundred questions on waterproofing) #79: How should the bathrooms and toilets in newly built construction sites be waterproofed? Which series of waterproof materials is best? Are there any blind spots that need special reinforcement?

A: (i) According to the waterproofing standards of the Japan National Association of Architects’ JASS 8, it is recommended to use a water-based composite waterproofing material (also known as the “elastic” waterproofing material commonly used in the market).

(One Hundred Questions About Waterproofing) #78 Waterproofing for Bathrooms: How should the choice of materials prioritize specific features and functions?

Answer: (1) The function next—since it is difficult to achieve complete dryness on the bathroom walls, it is best to use water-based waterproofing materials. (2) Weatherproof function—since the bathroom surface is exposed to the elements, it is necessary to use a waterproof material that can withstand the elements.

(One hundred questions about waterproofing) There is often a white coating (wall cancer) on the wall #77near the bathroom. Why does it form? If construction is not carried out from within the bathroom, what are the feasibility issues if construction is carried out from the outside wall?

Answer: (i) The water in the bathroom is heavy, while the water outside the bathroom is light. The water in the bathroom is acidic because it combines with the carbon dioxide and carbon monoxide in the air to form acidic water. These acids

(One Hundred Questions on Waterproofing): What are the common types of #76bathroom leaks?

Answer: (i) Longitudinal leakage (water leaking from the upper floor to the lower floor): (1) Water leakage from the lower floor caused by cracks in the bathroom floor or defects in the floor structure. (2) Due to drainage pipes

(One Hundred Questions About Waterproofing) After the introduction of the #75-thread method for injecting PU foam, what is the reliability of the leak repair using this commonly used method? How reliable is the use of transparent water-repellent agent to repair window frames?

Answer: (i) Although this method of construction has the advantages of being quick and low-polluting, the actual results have the following blind spots: (1) The construction workers must possess proficient skills and wisdom;

(One Hundred Questions on Waterproofing) After the #74new construction site is handed over, due to poor installation of the window frames, what are the various repair methods for fixing the leakage?

A: The phenomenon of water leakage caused by poor installation of window frames is the top priority for the after-sales service departments of major construction companies in China. Their repair frequency is high. Their repair techniques for fixing leaks mainly include:

(One Hundred Questions on Waterproofing) #73: Is it possible to waterproof new construction window frames using water-based acrylic waterproofing paint? If there is sufficient budget for high-end luxury homes, what is the most durable and best waterproofing method?

Answer: (i) Using water-based cured asphalt paint to waterproof window frames: experience shows that this black waterproof adhesive (which is labeled as "water-based PU" on the market but is actually not)

(One Hundred Questions on Waterproofing) Question #72: Can the gaps in doorways and windows that are too large be filled with quick-drying, quick-setting cement mortar sold by general building materials stores for construction? What are the potential side effects?

Answer: Currently, the emergency grout sold by building materials stores is mainly used for basement leak detection projects. If it is used to fill large gaps in door and window frames, the following side effects will occur: (1) This

(One Hundred Questions on Waterproofing) #71: Since the design or layout changes have caused the gaps between the window frames to be too large, is it possible to first fill them with red bricks? What are the key points to consider regarding the waterproofing?

A: This is a common situation in construction sites. Many site managers lack basic knowledge of waterproofing, which is one of the main reasons why water seeps everywhere from the walls near the window frames. Generally speaking

(One Hundred Questions on Waterproofing) #70Generally, new construction sites will install waterproofed groove for windows and doors. However, contractors are strictly required to apply waterproof agent during construction. Why is there still a frequent occurrence of water leakage? How can it be prevented?

Answer: (i) The author believes that the problem of waterproofed window and door joints is a very important aspect of the construction process (have you noticed how many construction sites are flooded with rainwater after a typhoon or continuous heavy rain?).

(One Hundred Questions on Waterproofing) There are many reasons for #69window frame leakage, and most of them can be divided into which categories?

Answer: It can be divided into two main categories: (i) leakage caused by poor processing of hardware components in the window frame itself or improper installation: (1) gaps or gaps in the sealing strip on the straight and curved parts of the window frame; and (2) gaps in the sealing strip on the curved parts of the window frame.

(One hundred questions about waterproofing) Question #68: Some people say that the expense of cladding the exterior walls is too much to bear; construction from the outside is also very extensive; why not just install tiles indoors to completely solve the problem? Is this a correct view? If it is not possible to do the cladding from the outside, can it be done from the inside?

Answer: (1) Of course, that is incorrect! This kind of backward construction that ignores the root cause of the problem while ignoring the symptoms is ultimately a waste of resources and a waste of labor. While it may have good results in the short term, as long as it is carried out over a long period of time, it will inevitably lead to even greater problems.

(One Hundred Questions on Waterproofing) Old-style apartments located on the #67th floor or below often have spider-web-like cracks in the exterior walls, causing indoor water seepage and wall cancer. How should waterproofing be repaired? After waterproofing is completed, the wall cancer problem still persists after the interior is repainted. How can it be resolved?

Answer: (i) The exterior structures of older apartments below the fifth floor are mostly made of reinforced brick construction, and the surfaces are mostly waterproofed with seven-inch stone powder or cement paint; if the mortar quality is poor or there are other external

(#66One Hundred Questions About Waterproofing) Houses with attics that have been converted into additional floors often have water seepage or peeling paint on the walls at the corner of the stairs. Why is this happening? How can it be prevented?

A: Almost half of the terraced houses have some kind of annoying water seepage phenomenon. Moreover, this water seepage usually continues even after the weather is sunny for several days. Generally speaking,

(One Hundred Questions on Waterproofing) #65 is limited by the building coverage ratio and the width of the alley; the exterior wall must be retracted into a sloped structure. If the exterior wall structure is completely remodeled, why is it particularly easy to leak water? How can it be prevented?

A: As shown in Figures A and B, after the renovation, due to the poor bond between the new and old concrete, it is particularly easy for leakage to occur at the joint area. This is an unavoidable defect that must be prevented beforehand. Preventing leakage

(One Hundred Questions on Waterproofing) How can we prevent leakage of water from indirect seams and shear stress cracks in exterior walls during construction of #64new projects? What are the construction standards for this?

Answer: It is recommended that construction companies separately bid for waterproofing for the external wall joints and the shear cracks near the windows before painting the exterior wall. This is because the cost of waterproofing beforehand is definitely much lower than the cost of fixing them afterwards.

(One Hundred Questions on Waterproofing)#63 Why are terraced houses with reinforced brick structures particularly prone to water leakage or the formation of wall rot? How can it be prevented beforehand? How can it be remedied afterwards?

Answer: (i) The causes of the leakage: (1) The red brick exterior wall leaks when subjected to earthquakes or structural subsidence, causing cracks to form; (2) The beams and the brick wall below

(One Hundred Questions About Waterproofing) The floor tiles in the room of #62Fengtu Wall will leak when it rains. Most of the time, what causes this? Why is this area particularly prone to leakage?

A: Most of the problems are caused by indirect seams in the exterior walls (especially in exposed beam areas). (1) Because the layers of the exterior structure are connected with

(One Hundred Questions on Waterproofing) #61 Why does the exterior of a building, even with only minor defects, cause the entire interior wall to become discolored or moldy? What is the most common mistake that decoration workers make?

Answer: (i) It is caused by water stagnating or accumulating inside the wall due to partial defects on the exterior wall. After the sun comes out, this water vapor forms, and during the evaporation process, it carries a significant amount of pressure (

(One Hundred Questions on #60Waterproofing): Apart from structural cracking (such as shear-induced cracks) that causes water leakage, what are the most common types of joint systems that cause leakage?

Answer: (i) Construction joint — A gap created by the overlapping of new and old concrete or the junction of RC with different materials.

(One Hundred Questions on Waterproofing) What are the different types of external wall leakage caused by #59? Because of the different structural designs, do they also produce different types of physical phenomena of leakage?

Answer: (i) Classification of reasons for exterior wall leakage: (1) Cracking caused by structural problems. (2) Leaking caused by improper connections between exterior wall layers. (3)

(One Hundred Questions on Waterproofing) In the open space courtyard in the #58th floor, water leakage has occurred due to cracking in the floor slab. If we need to repair and renovate the water leakage on the courtyard, it would be too much trouble. Is it possible to repair the water leakage directly from the ceiling in the ground floor? What are the various methods of repair?

A: The courtyard leaks due to cracks in the construction of the ceiling from the basement; if the construction method is correct and the techniques are proficient, the chance of stopping the leakage can be as high as over 70%. Generally, there are only a few methods to follow:

(One Hundred Questions About Waterproofing) What are the differences between waterproofing for #57hot spring pools and swimming pool waterproofing? What is the best method of construction?

A: The main difference between the waterproofness of a hot spring pool and a swimming pool is that the pH value must be resistant to acid and alkali—(1) The area of a typical hot spring pool is relatively small, and it is generally constructed using the FRP method. However, due to the

(One Hundred Questions About Waterproofing) What are the common construction methods for swimming pools in recreational areas of #56new construction sites? And what is the best construction method?

Answer: (i) The most commonly used method on the market today is the five-layer FRP construction method (that is, a three-layer unsaturated polyester coating with two layers of glass fiber mesh sandwiched in between). The waterproof performance of this method

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