What is Foam Roofing?
Primarily used on commercial properties, foam roofing is gaining popularity among homeowners because of its durability and energy efficiency. Spray Polyurethane Foam (SPF) has been used as a roofing and insulation material for over 45 years. In that time, SPF has gained a reputation for being dependable, long lasting, and very affordable. Now there are foam roofs that have been in place for decades, and industry experts believe that they should be able to last indefinitely as long as they are properly maintained through recoating.
SPF is a combination of isocyanate and polyol. To install, these two components are fed through a proportioner which heats then pumps the two separate components (in a 1:1 ratio) to a spray gun, where they are mixed and sprayed onto the substrate (your roof deck). A chemical reaction then takes place and the mixture, sprayed as a liquid, expands 20 or 30 times to form a solid, lightweight, monolithic closed-cell mass. When sprayed on a roof deck, it provides excellent water resistance and thermal insulation because it is seamless, leaving no joints for rainwater to leak through to your interior or for air conditioning to escape from your home.
SPF can be applied over an existing roof, but it does requires a clean surface for proper application. It must be dry and free of contaminants like oil. The final step of the process is the application of a protective elastomeric topcoat. The topcoat is essential to protecting and sealing the SPF from potential damage caused by the sun’s UV rays, stretching (due to temperature changes), moisture, and fire.
SPF is significantly lighter than traditional roofing systems like asphalt, putting less stress on the frame of your home. SPF is also able to prevent standing water, a common problem with conventional roofing systems. To do this, your installer will build up areas of greater foam thickness while spraying so that water will drain properly. Without this safeguard, water accumulation could lead to roof collapse.
Cost of Foam Roofing
Foam roofs start at around $1.65 to $2.50 per square foot installed, but could cost as much as $3.00 to $6.00 or more per square foot. Assuming a roof size of 1,500 square feet, that’s a total estimated cost of $2,475 to $9,000. In addition to the low installation cost, joint-free foam eliminates the need for costly repairs to fix roof leaks. Also, because SPF is so dense, you may be able to save money on attic insulation costs.
Energy Efficiency of Foam Roofing
As much as 40% of your home’s energy is lost due to air infiltration. SPF prevents even the smallest gaps, cracks, and holes from which valuable energy could escape. SPF has the best insulating properties currently available. SPF roofs also reduce thermal shorts, because unlike shingles they do not require metal fastening since the foam bonds directly to the roof deck in a continuous layer of insulation. The Department of Energy estimates that 56% of the energy used in your home goes toward heating and cooling, so using SPF as a safeguard against energy leaks will have a big impact on your monthly utility bills.
In terms of your environmental footprint, SPF roofs can also be applied over your existing roof, saving significant demolition costs and diverting waste from local landfills–traditional roofing products contribute an estimated 20 billion pounds of waste to U.S. landfills on an annual basis.
Maintenance of Foam Roofs
Every 10 or 15 years, depending on the type and amount of coating installed, your roof will need to be cleaned, primed, and recoated. If this is done, then a good-quality SPF roof could last 50 years or longer.
Common Concerns with Foam Roofs
SPF has to be installed under very specific weather conditions. There is a narrow range of outdoor temperature and humidity levels in which SPF can be installed and not adhering to those guidelines can compromise the integrity of the roof. Even trace amounts of surface moisture on the substrate can result in the foam’s failure to adhere correctly. The optimal climate for applying an SPF roof is warm and dry with no wind. Depending on where you live, you may have to wait months for the perfect conditions.