Spray Foam Roofing System
Spray polyurethane foam (spray foam) roofing systems provide a durable, waterproof covering that bonds tightly to nearly any properly prepared substrate. Spray foam is created when two liquid components are properly mixed. This forms a rigid polyurethane foam surface. It is so lightweight, about eight ounces per square foot, that it can be applied over most existing roof systems without exceeding the structural load capacity, yet it easily withstands foot traffic and other weight requirements.
Unlike some systems, spray foam roof systems can easily be re-coated with elastomeric roof coatings, thus extending the life of the roof. Most of these roof coatings are white which reduces the heat load as well.
Tillotson typically uses SPF roofing manufactured by BASF Chemical or Conklin Roofing Systems.
Spray foam roofing also offers the advantage of being self-flashing. During installation, the spray foam flows around all protrusions, such as roof vents and cooling units, forming a tight bond that seals off places where leaks tend to start.
The final step in a spray foam roof is the application of a quality elastomeric roof coating. Once this is cured it forms a seamless and flexible covering that protects the spray foam from sunlight and moisture, while the white coating helps make the roofing system even more energy efficient.
Spray Foam Roofing Application
Spray Polyurethane Foam (SPF) roof system is applied using a specific spray gun that mixes two chemicals as the trigger is pulled, causing a chemical reaction that produces the end product. Spray foam is usually applied in thicknesses from a minimum of one inch to several inches, depending on the amount of insulation value that is desired. Polyurethane foam is a plastic and is waterproof after it is applied, however, it needs protection in the form of a coating system or a layer of rock to help it resist the UV rays in sunlight and to keep it from deteriorating.
Spray foam used for roofing is flexible enough to be able to move with the expansion and contraction of the roof but hard enough to withstand foot traffic, impact, wind and weather.
Spray foam is able to be applied over a variety of substrates with ease. As a roofing material, SPF is difficult to beat if the applicator is using a high quality coating and properly applying the product. If, on the other hand, substandard equipment is used and the ratio between the chemicals is incorrect, it can cause bubbles or blisters in the foam potentially creating problems down the road. The same problem can occur when applying foam roofing over a wet substrate.
Tillotson Enterprises applies SPF at a thickness of no less than 1.5 inches, half an inch above the minimum one inch recommended by the Spray Polyurethane Foam Alliance (SPFA). The SPFA is the governing body of the foam industry. Some contractors will apply a half-inch or less which will lead to problems and added cost to properly repair.
Among the advantages of SPF is that it creates a continuous and seamless membrane; with every square inch fully adhered to the roof deck. This means that if a puncture is created in the coating layer it will not create a leak because water cannot travel through the foam. In fact, if a hole is made all the way through to the roof deck, a leak still may not occur because the foam is fully adhered at every point. Yet if the same hole were formed in a single-ply roof, the water would spread throughout the roof deck, finding any number of holes caused by the screws holding down the sheet system.
SPF roofs are also referred to as a renewable roof system, because if the roof has gone too long without attention: any bad areas can be cut out and re-foamed, and settled areas can be filled in with additional foam. The largest savings from utilizing SPF on a roof, comes in the form of energy efficiency. Each inch of foam roof has an R-value of around R7; and then a white protective coating system is applied which helps reflect sunlight and make the roof even cooler. R-Value is a measure of insulation’s ability to resist heat traveling through it. Most SPF systems pay back the cost of the roof due to energy savings alone in just a few years. In addition, the cost of renewing the coating system over the SPF roof will be substantially less expensive than re-roofing over other systems.
Advantages of Spray Foam
Spray foam roofs, sometimes referred to as spray on roofs, have several advantages.
- Spray Foam Roofs form a seamless roofing system. To be seamless means it has no joints or seams that often allow outside water and air to pass through the roofing system into the building structure.
- Spray on Roofs eliminate flashing leaks because a spray foam roof conforms to the substrate when installed, this seamless system is ideal for flashing parapet walls, equipment, skylights, and cooling towers. Many roof leaks are caused by faulty flashing, and spray foam roofs solves this problem.
- Spray Foam Roofs can eliminate troublesome ponding water in re-roofing applications, ponding water may be eliminated by adding an increased thickness of roof insulation in low areas. Building up the low areas and sloping the roof so that it drains properly will eliminate ponding water. It will also help reduce additional weight load caused by this water accumulation.
- Spray on roofs are lightweight and are excellent for roof insulation. The weight of roof insulation is around 3 pounds per cubic foot. One inch of foam roofing weighs approximately 60 pounds per 100 square feet. This is considerably less when compared to approximately 600 pounds per 100 square feet for a conventional, four-ply, built-up roofing system. This makes a spray foam roof system ideal for re-roofing, as it is possible to apply over an existing built-up roof without removing it.
- Spray foam roofs have the highest “R” Value. A spray foam roofs has an aged “R” value of 6.2 – 6.5, enabling it to provide more thermal resistance with less material than any other roof insulation. In most cases, a spray foam roof will pay for itself in 5-8 years in energy savings.
- Foam roof insulation is chemically stable. Spray foam for roof insulation is inert, but this type of roof insulation has to be protected from sunlight by a U.V. resistant elastomeric roof coating system.
- A spray foam roof is odorless, resists attack by either mildew or fungi and has no nutritional value. There are no bad odors for you or your neighbors while spray foam roofing is being applied.
- Foam Roofs minimizes thermal shock due to characteristics such as being seamless, having a high “R” value, and being protected by a white elastomeric coating, spray foam roofing is able to greatly reduce the effects of thermal shock on a structure.
- Spray on roofs have great versatility. Spray foam roofs can be used on both new construction, as well as to replace old roofs. Spray foam can be applied to flat, pitched, saw-toothed, and domed or having unusual slopes or configurations. Spray foam is also an ideal spray application for tanks, freezers, coolers, piping, duct-work and various other odd jobs.
- Spray foam roofs are rigid. While spray foam roofs are very lightweight, these spray on roofs are also strong and will not pack down or sag.
- Foam Roofs are flexible and have the ability to withstand normal expansion and contraction without affecting the ability to keep the structure protected from the outside elements.
- Spray on roofs are watertight. Spray foam roofs are composed of billions of minute closed cells which resist the penetration of water and vapors. It must, however, be protected by an elastomeric roof coating or crushed rock for use in an outdoor environment.
- Spray foam roofs are long lasting. The elastomeric roof coating system, which protects the spray roof insulation, can be rejuvenated by the re-application of additional roof coatings. This doesn’t take place until the initial coatings system has weathered after many years of service. The normal wear of a quality coating has a life span of about 15-20 years.
- Foam Roofs have little disruption to building owner during application. A spray foam roof system can be applied in a relatively short period of time with little or no disruption of building operations. This is due to little or no tear off of the existing roof, and little manpower needed to apply the spray foam roof.
Tillotson typically uses spray foam roofing systems manufactured by BASF Chemical or Conklin Roofing Systems, who are leaders in the field. Tillotson staff are manufacturer trained and certified by both companies. Spray on roofs are easy to maintain minor repairs or modifications to a spray foam roof system can be made by in-house maintenance personnel at minimal cost.