Improving SPF

• Photo courtesy of Lapolla Industries Inc., Houston

In the roofing industry, there is an increasing need to provide building owners with durable, long-lasting roof systems that combine high-energy performance, enhanced wind-uplift capabilities, air retarders and low maintenance costs.

With the increased need for building envelope tightness has come a renewed interest in spray polyurethane foam (SPF) roof and wall systems. As you probably are aware, SPF roof systems have been around for more than 40 years. However, many roofing professionals still lack a basic understanding about how to specify, install, inspect and maintain these systems—this lack of knowledge stems from the fact that the SPF industry has not effectively trained installers and educated building owners and specifiers compared with traditional roofing sectors.

SPF conforms to unusual substrates; provides a seamless system after completion; features high thermal resistance and tenacious adhesion; is lightweight; and creates an immediate air barrier, enhancing buildings' energy efficiency. SPF roof systems have performed under demanding conditions, such as hurricanes and other severe weather conditions, resulting in minimal damage to buildings' roof systems and interior contents.

The question is: Why aren't more people choosing SPF roof systems in lieu of traditional roof systems? The answer is largely because of people's misconceptions about SPF roof systems, such as that SPF absorbs water easily, is soft and spongy, and will be crushed if walked on. Also, people confuse SPF with open cell foam, which is used in insulation and roof systems.

Product evolution

The SPF manufacturing industry has come a long way by continually improving the physical properties of the materials and equipment used in SPF roof system installations. During the early 1990s and again in early 2000, the Environmental Protection Agency (EPA) required SPF manufacturers to completely reformulate their blowing agents. As a result, the SPF industry learned to develop specific testing to ensure performance was either equal to or better than the performance of SPF's earlier versions.

In addition, new performance standards were developed by ASTM International and SPF manufacturers to ensure the SPF industry used appropriate methods to measure performance and that all manufacturers met these requirements for product performance and the reporting of these physical properties.

Based on the new formulations, SPF equipment manufacturers responded to applicators' new needs. Improved circuitry within the spray equipment inside the SPF trailer, electronic monitoring of the mixing process of the two material components, and increased capacity of heating and output were addressed to ensure optimum system performance. Equipment and SPF manufacturers continue to work together to develop the next generation of SPF mixing and installation components.

It is safe to say manufacturers, trade organizations, code bodies and other regulatory entities have created an even playing field regarding material and equipment standards. What is left is the quality of the installation to provide a watertight condition to protect the building envelope.

Quality installation

As with all roof systems, proper application of SPF systems is required for long-term success. During the past two years, I have had the opportunity to inspect various SPF roof systems throughout the U.S. ranging from 1 to 5 years old, 5 to 10 years old, 10 to 15 years old and some as old as 30 years. The results, though not visually pleasing in many cases, were no different from what is seen with traditional roof systems.

The desire for quantity has taken over the mandate for quality because manufacturers and contractors often place a higher value on volume and speed than quality and training.

The SPF industry's future heavily depends on the technical skills of applicators and the pride they take when installing SPF systems. Equally important is applicators' ability to follow guidelines outlined by SPF manufacturers, specification documents and local building code guidelines.

SPF manufacturers have training programs designed specifically to educate contractors and installers about their products and application guidelines. In addition, each manufacturer has instituted training programs developed with government agencies that ensure a minimum level of expertise is in place for the handling of chemicals used to create SPF. These programs are the first step in the process of these groups working together to ensure safe, proper construction and proper product selection.

My company, Lapolla Industries Inc., Houston, has instituted a contractor safety awareness program that requires contractors to review the most current information available regarding SPF safety and application.

This program is a result of Lapolla Industries' interaction and participation in industry organizations such as the Center for the Polyurethanes Industry, which is part of the American Chemistry Council, and Spray Polyurethane Foam Alliance (SPFA). Both organizations work with EPA, the National Institute for Occupational Safety and Health, and Occupational Safety and Health Administration to ensure safety.

Good manufacturers offer training specific to each application, ranging through the entire spectrum of interior insulation and roofing materials, as well as required or requested on-site assistance.

Open communication

For the SPF industry to continue to succeed, I believe manufacturers, SPFA and SPF contractors must not forget about the basics of roofing. A thorough pre-job inspection should be performed before a project is estimated, and all details should be documented. Core cuts should be performed to identify existing conditions, and a moisture scan should be performed to identify any existing moisture.

For re-cover projects, how an existing roof system is attached should be determined, including identifying the underlying deck. Attachment is critical because it will affect an SPF roof system's wind-uplift capabilities, especially if a project is located within a high-velocity hurricane zone or a building is insured by FM Global.

After contractually securing a project, the estimator, project manager and installer(s) should meet. Often, estimators are left out until after projects are secured. The project manager and/or installer needs to understand the estimator's logic before executing a project. The best place to perform this meeting is on the roof in the presence of the owner or owner's representative because an owner's expectations may differ from those of the other parties. Because of owners' possible lack of understanding of SPF roof systems, communicating with owners is key to SPF roof systems' overall success.

One area of misunderstanding is foam blisters. Foam blisters are becoming a growing concern for many building owners, consultants and design professionals because they are not aesthetically pleasing. To address these concerns, SPFA has produced a document titled "Spray Foam Blisters" that outlines blisters' causes, types, prevention methods and repair methods.

Often, SPF blisters are stepped on or kicked open, which leads to criticism of SPF. Although, in my opinion, blisters do not occur more frequently in SPF roof systems than in traditional roof systems, they are inspected closely because owners and specifiers often are unfamiliar with the product.

After the final protective coating is applied over an SPF roof system and cured, the applicator should inspect the area for thin coating application, pin holes, blisters and cracks. Proper quality-control measures and any necessary repairs should be completed before departure from the project.

A valid option

SPF should not be looked at as a less expensive roof system or a quick way to seal a building. Building owners and design professionals should educate themselves about SPF and its benefits before making a roof system buying decision.

Shirad Ali, RRO, is director of engineering and applications and roofing systems product manager for Lapolla Industries Inc., Houston.