Originally, the phrase “cold-applied roofing” described  solvent-based built-up roofing (BUR) that did not require heat to install. Today, the term today has a significantly broader meaning, and includes cold process built up roof systems, cold adhesive bitumen membranes, and liquid-applied membranes.  This last category, sometimes called “elastomeric roof coatings,” were first developed in the mid-1970s and are based on rubbers, acrylics, acrylic emulsions, and/or polyurethanes.

Monolithic liquid-applied roofing blurs the line between roof coating and roof membrane system. Typically made of high-tech polymeric resins, liquid cold-applied roofing (also called “fluid-applied roofing,”) involves applying a liquid-based coating to a roof, which cures to form a rubber-like elastomeric waterproof membrane. 

Because these membranes are monolithic and self-flashing, they’re an excellent choice for roofs with difficult flashing details, shown here on the roof of the Freedom Tower in Manhattan.

This coating can be reinforced with secondary materials to provide additional tensile strength, but often, no reinforcing material is needed as the liquid itself cures to a tough, rubber-like membrane. If reinforcing is needed, it’s usually applied as a single layer, unlike cold-process BUR.

“Cold liquid-applied systems offer significant advantages over sheet products,” said Andreas H. Wiggenhagen, president of Kemper System America, Inc. “They eliminate seams–and the expense of installing flashing and termination bars. They also are ideal for sealing difficult areas such as skylights and foundations, and around multiple penetrations such as stanchions and pipes.”

Because these membranes are applied as a liquid, they’re monolithic (no seams) and are typically considered self-flashing, so it’s an excellent choice for roofs with difficult flashing details. 

The lifespan varies, depending on conditions and materials, but is typically about 25 years.

Liquid roofing is especially cost-effective as a repair technique, and can be used over a wide variety of substrates, including concrete, metal, and many existing roofing materials.  Overtopping an aging roof with a liquid-applied membrane averages 70% less expensive than a traditional remove-and-replace roofing upgrade.  

They are used right out of the drum or pail and applied using a notched squeegee. Many formulations can also be applied via brush, spray, or roller, depending on the viscosity of the product. 

Contractors can install these systems without investing in expensive kettles; often opening a bucket, pouring, and spreading is all that is required.

 Doing away with the big, messy hot kettles and fumes allows for safer handling of materials, a lower level of odor at the job site, and fewer complaints from building occupants.  Cleanup requires only wiping down the squeegee and disposing of the drums and pails.