Engineering:Liquid roofing

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Two component liquid rubber spray system

Liquid roofing is the process of waterproofing a roof by the application of a hydrophobic liquid roof coating. It can be applied to most roof styles, including flat, pitched, and domed roofs.

History

The concept of liquid roofing dates back to the early 1800s, when natural bitumen was combined with various materials for waterproofing. Over the years, liquid roof coatings evolved, with early coatings based on liquified rubber in the 20th century. Advancements in the 1960s and 1970s introduced acrylics, acrylic emulsions, styrene-butadiene, and unsaturated polyesters, leading to improved quality and durability. In 1975, the first water-based elastomeric roof coatings were introduced, and in the late 1980s, single-component moisture-cured polyurethane coatings were developed, forming the basis of modern cold liquid roof coating technologies.[1]

Concept

A typical liquid roofing installation

Liquid roofing involves the application of a monolithic, fully-bonded, liquid coating to a roof. The coating cures to form a rubber-like elastomeric waterproof membrane capable of stretching and returning to its original shape. 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 most traditional roofing materials, including felt, asphalt, bitumen, and concrete.[2] Liquid spray-applied roofing membranes have been one of the fastest growing roofing systems in North America and Europe.[3]

Benefits

Cost Effective

The process of liquid roofing provides a cost-effective method of making a new or existing roof waterproof because it is potentially less expensive than overall roof replacement for refurbishment.[4]

Safety

Unlike the installation of felt, asphalt and bitumen membranes, liquid roofing does not involve hot equipment. The coating material used in liquid roofing process is applied at ambient temperatures, thus mitigating fire risks posed by hot roofing equipment.[3]

Encapsulation

When applied, liquid roofing creates a coat that protects the surface underneath from weathering. This is especially desirable when working with asbestos roofs, as attempted removal of asbestos roofing can damage it and release material that can induce asbestosis. Using a liquid coating system seals the asbestos and makes disturbance of the material more difficult.

Easy application

The application is simplified by fast curing in and resistance to extreme temperatures (between -40 °C and 80 °C). Minimal equipment is needed in installation.

References