Answer:
1. In the decision-making process regarding the selection of waterproof materials, some insist on using a certain material, while others insist that a certain material should not be used. Ultimately—these are all the results of accumulated experience, and these accumulated experiences are painful experiences of failure that form the conclusions in the future.
2. In fact, from a professional construction perspective, the above approach has the disadvantage of “seeing trees but not the forest.” The aforementioned decision-makers have accumulated their experience in managing at most 20 to 30 projects, but I have been involved in waterproofing projects for over 40 years. I have handled over a thousand projects of various sizes, and I have used most types of waterproofing materials. The conclusion I have reached is that all waterproofing materials worldwide, regardless of whether they have been on the market for more than five years, have their own advantages and disadvantages, and each has certain functional properties. “Appropriate materials for the appropriate application” is the most important principle.
3. Most luxury homes insist on using the five-ply or seven-ply oil-resistant felt specified in CNS 10416, citing that five-ply oil-resistant felt is the most trusted and used in Japan. In fact, due to the construction of five-ply oil-resistant felt requires applying the bitumen at a high temperature of about 200 degrees Celsius, and the timing must be precisely controlled, work-related accidents are inevitable, and construction workers in Taiwan are already gradually declining (there are many who lack technical certificates and are just filling in the gaps). In Japan, its market share is also decreasing year by year (from nearly 70% a decade ago to about 30% this year), and furthermore, the Environmental Protection Agency’s air pollution control is becoming increasingly strict! Please ask, if the same material can achieve long-lasting effective waterproofing, why is it necessary to choose something that cannot be used?
4. The water-resistant and weather-resistant properties of the tensile oil felt are certainly not a problem; however, Japanese construction sites have flat roofs with excellent water drainage, and the roofs are not used for any other purpose. On the other hand, roofs in Taiwan are often used for other purposes, so there are many areas with twists and corners, and even a slight carelessness in construction can lead to failure.
5. In Taiwan, some construction companies still insist on applying five-ply or seven-ply anti-tear oil-coated felt to the interior walls, including the courtyards, flower beds, water basins, and decorative panels. They cannot arbitrarily change the materials. Please ask: How can you install the asphaltic concrete with temperatures exceeding 200 degrees Celsius on the walls? This insistence completely violates the principle of using appropriate materials for the intended purpose.