Polysulphide and Polyurethane Sealant

The concept of liquid waterproofing has existed from the early 1800s, when natural bitumen was combined with jute, straw, rag felt and other man-made materials to provide a waterproofing solution for roofs. In the early twentieth century the manufacture of liquid roof coatings became a commercial activity, with the earliest coatings being based on liquefied rubber. The 1960s and 1970s saw the introduction of acrylics, acrylic emulsions, styrene butadiene`s and unsaturated polyesters, which led to improve quality and durability of the coatings. In 1970s the first water based elastomeric coatings where introduced. In the late 1980s, single component moisture-cured polyurethane based liquid membranes were developed and remain the basis of most of today`s cold applied liquid roof coatings technologies. Liquid roofing involves the application of a monolithic fully bonded, liquid based coating to a roof. The coating cures to from a rubber- like elastomeric waterproofing membrane, capable of stretching and returning to its original shape without damage. Such coating systems are usually reinforced with secondary materials such as glass reinforced plastic to provide additional tensile strength. The coatings can be applied over concrete.