Upgrading C&I rooftop solar installations with spray polyurethane foam

spf diagram

SPF acts not only as an additional barrier to the elements, but it is also incredibly insulative.

As we have continued our expansion in the commercial and industrial solar market (which includes commercial, industrial, municipal, university, school, cold storage, food-processing and hospital buildings), we’ve discovered something. If commercial building owners are not overly familiar with how solar arrays are installed, they have legitimate concerns about the potential effects solar arrays could have on their roofs. For example:

  • Will the racking system, which holds the solar modules in place, harm the roof?
  • Will it have to be penetrated, creating potential pathways for the elements to enter?
  • Will it shorten the longevity of the roof?
  • Will it void the warranty?

In addition, we’ve discovered it’s often not just solar that these building owners want. They are often looking for energy-efficiency measures, too, particularly as property assessed clean energy (PACE) programs allow them to pay for both kinds of upgrades through their property taxes.

At Standard Solar, we take those concerns and desires seriously, and we’ve been searching for an all-encompassing solution — and we believe we have found one in spray polyurethane foam (SPF).

SPF acts not only as an additional barrier to the elements, but it is also incredibly insulative. As a result, building owners who use SPF as an underlayment to their current roofing will reduce energy consumption and save money on their energy bills.

Let’s take a closer look at how SPF works and how it will help you reach your solar and energy efficiencies goals.

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Longevity match

One of the strongest arguments for installing a rooftop solar array on a commercial building is to provide electricity for the building for at least 25 years. Many roofing materials can’t match that lifespan, but SPF can — and reduce energy bills by 20 to 50 percent more than fiberglass insulation in the process. When the proper roofing material is wedded to a rooftop solar array, the building owner can stop worrying about either. Instead, they can spend their time counting the savings the electrical system and energy-efficient roof will provide them.

Penetrating protection

In areas with high winds, on metal buildings and other external factors that could adversely affect solar arrays (think earthquakes), arrays must be attached to the roof. To accomplish this, solar installers are often forced to penetrate the roof membrane.

Penetrating installations are the cause of sleepless nights for building owners. After all, the solar installer is asking to poke holes through part of a structure that costs significant money. Any poorly sealed holes will cause problems for the roof itself and potentially allow rain or wind to reach beneath the roof and damage the inside of the building.

Unfortunately, some solar installers don’t know what it takes to seal the penetrations properly, and as anyone who’s ever had a leaky roof knows, locating the problem is difficult by the time the damage is discovered.

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That’s where SPF can help. We often use SPF to restore roofs under the arrays we install. When you combine SPF with a quality liquid membrane, not only do they self-flash, but they provide a double measure of protection from the weather. Finally, having a sturdy underlayment adds even more strength to the roof, making it an even better investment for the building owner.

The best use of SPF roofing we’ve seen, however, is at building conception. If the long-term plan is always to add a solar array to the roof at some point, SPF roofs allow the construction company to make the building “solar ready” by installing solar stanchions (legs).

Building owners can speed solar installations with such advance planning and get to the fun part of having a solar array — saving money — more quickly.

Perfect pairing

Like a perfectly prepared filet and a well-rounded pinot noir, SPF roofs and solar arrays beautifully complement each other. Combined, they allow commercial building owners to save through solar electricity production and improved energy efficiency with the outstanding insulative properties of SPF and the reflective characteristics of a quality liquid membrane. This collective approach will help companies reach their sustainability goals faster and with greater success.

Though SPF is currently something of a niche product, we believe it is gaining a much wider following with each successful installation, among both solar installers and commercial building owners. In time, we believe it will displace conventional insulation methods, which will be good news for building owners and solar installers alike.

Daryl A. Pilon, M.E., is director of business development for Standard Solar.

— Solar Builder magazine

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