Answer:
(1) Using water-based cured asphalt paint to waterproof window frames: from experience, it has been shown that this black waterproof adhesive (which is all labeled as "water-based PU" on the market, but in fact is not—there is currently no factory in Taiwan that produces water-based polyurethane PU; all of it is a mixture of emulsified asphalt and acrylic resin mixed together) since it is water-based, it is also prone to re-emulsion and hydrolysis phenomena, especially when it is applied after a few months of installing tiles on the finished surface. In the event of a heavy rain over several consecutive days, the rainwater that enters the waterproof layer from the tiles and the paint coating will turn into highly alkaline rainwater, which is easy to begin to break down the original black waterproof adhesive from the surface, resulting in a paste-like liquid that then flows out through the tile seams, destroying the entire appearance of the building. Therefore, caution must be exercised!
(ii) In my experience, the best construction method is a composite system where the mud is used to complete the mortise and the surrounding area is then coated with a single-fluid PU filler and elastic cement.
