by Keegan Tune | Senior Branch Manager | Saint Louis Roofing Branch

Did you know? A form of liquid roofing was first used in the early 1800s when natural residue from petroleum distillation, called bitumen, was combined with jute, straw, rag felt, and other materials to waterproof roofs. It wasn’t until the early twentieth century that liquid roof coatings became commercially manufactured and more widely used.

Today, with so many systems and high-performance coatings available, facility managers may have difficulty knowing which type of liquid applied roofing to use and when and where to use it for the best results.

Liquid applied roofing has many benefits in relation to its cost, performance, and ease of installation. Plus, it is well suited for most roof structures and can be applied over most traditional roofing materials, including concrete, copper, bituminous, metal, tile and PVC/TPO/EPDM. When applied correctly by an experienced specialty roofing contractor, liquid applied roofing can provide up to 25 years or more of solid performance.

Liquid Roofing System vs. Coating System

There is a big difference between a liquid roofing system and a coating. A liquid roofing system is a thicker reinforced membrane (50+ mils) that requires additional application steps and costs more than a traditional roof coating. With a liquid applied roofing system, building owners receive a labor and material warranty similar to a traditional roof. Coatings are typically not reinforced, are a thinner membrane (23-40 mils) and are less expensive, but the warranty typically only covers the materials.

Financial Benefits

Liquid applied roofing systems are typically used to restore an existing roof, although they can be used in new construction. Liquid applied roofing can increase the useful life of an existing roof without having to add an additional layer of roofing on top of a structure. A maximum of two layers is recommended for a traditional roof.

A liquid applied roofing system is categorized as a roof repair and could potentially cover two traditional roofing layers. The cost of a liquid applied roofing system can also be depreciated within the year that it was performed, whereas a traditional roof replacement is depreciated over 29 years. Since liquid applied roofing is considered a roof repair, building owners could potentially charge their tenants for the expense, depending on how their lease is written. 

Sustainability Benefits

Liquid applied roofing is a sustainable option:

• Saves landfill space from traditional roof tear-off materials
• Cool and reflective for energy savings
• Low VOC options are available to reduce air pollution
• Fewer material quantities are required for installation
• Maintain and re-coat for the life of the structure

Versatility Benefits

Liquid applied roofing provides a monolithic, seamless roof that can be easily applied around difficult-to-flash areas. While not ideal for every roofing situation, liquid applied roofing is recommended for difficult-to-access and busy roofs with a lot of penetrations, such as hospitals and high-rise buildings.

Additionally, there are many material choices and colors available at varying price points for liquid applied roofing.

Occupant Friendly Benefits

A worker with a bucket and a roller installing a liquid applied roof is much less intrusive and noisy than workers performing a full-roof replacement on a building. A liquid applied roof also takes less time and equipment to install than a traditional roof, the materials typically give off fewer odors, and there is a lower risk of water intrusion – always a major concern on a traditional roofing project.

Liquid membrane roofs are not a one-size solution for every roofing scenario, and not everyone has the expertise to install them properly. In many ways, liquid roof systems require more craftsmanship and expertise than the installation of a traditional roof. With liquid applied roofs, workers are essentially manufacturing a roof on a building and not in a factory. Identifying the substrate and the wetness of the existing roof, performing the proper substrate prep work and determining which system and primer to use are key to a successful project outcome. Liquid applied roofing may not be the cheapest roofing solution, but when applied correctly, liquid roofs, in the long run, are a very good value.

For building owners considering a liquid applied roof, continue to maintain the existing roof and repair any leaks, with the goal to keep good roofs in good shape. Contact a roofing professional, whether that’s a contractor or a consultant, to do an investigation, core sampling and scan of the roof to determine whether it is a viable candidate for a liquid roof system. Owners should also plan ahead to allow adequate time for these projects to be planned and the materials to be ordered and obtained. Finally, account for contingencies. Despite the best planning, in roofing projects, there are always unforeseen delays, particularly with the current material shortages and price escalations. Be sure to provide additional funding in the roofing budget to compensate for the current economic environment.