Position Paper: Installing Rooftop Photovoltaic Systems
With growing demand for photovoltaic (PV) systems and an increasing use of rooftops
as their natural home, roofing industry stakeholders, including the National Roofing
Contractors Association (NRCA), the United Union of Roofers, Waterproofers and Allied
Workers, the Center for Environmental Innovation in Roofing (Center) and Roof Integrated
Solar Energy (RISE) want to ensure these systems are properly installed, taking
into account a number of crucial factors of which building owners, designers, installers
and utility companies should be aware.
These industry stakeholders are unified in recommending rooftop PV system installation
always involve a professional roofing contractor and, when necessary, a licensed
electrician. The involvement of a licensed electrician is necessary to oversee the
proper installation of a PV system's electrical components, and, in most jurisdictions,
there are requirements for licensed electricians to perform that function.
NRCA, the United Union of Roofers, Waterproofers and Allied Workers, the Center
and RISE also recommend rooftop PV system installation only can be undertaken with
the involvement of a professional roofing contractor employing skilled roofing workers
for a number of reasons, including:
- The roofing contractor will assess the roof's condition. Installing an expensive
PV system over an aged or faulty roof system will lead to unintended results.
- The roofing contractor knows how to install new roof systems properly and safely
to best accommodate rooftop PV systems.
- The roofing contractor is aware of local building code requirements that pertain
to the installation of the rooftop PV system. These requirements typically include
provisions for wind resistance and fire resistance; simply installing a rooftop
PV system over an existing roof system can lead to building code violations if not
done properly.
- The roofing contractor knows how to organize a roofing job site, properly load materials
on the roof, and keep building occupants and passersby free from risk.
- The roofing contractor is trained—and insured—for safety on the rooftop. Falls remain
one of the primary sources of injury in the roofing industry. Workers who are not
aware of best safety practices or Occupational Safety and Health Administration
requirements not only put themselves in danger but also may be putting the building
owner at risk.
- Skilled roofing workers, including highly trained journeymen and apprentices, are
proficient in the application of all roof systems. They understand PV technology
and the types of PV applications used in roofing, have received extensive safety
training and recognize the unique safety hazards associated with PV roof systems.
- In addition, roofing workers are insured for worker's compensation at a rate appropriate
for work on rooftops. That is not likely to be the case for other tradesmen, and
disputes easily can arise in the event of a claim.
- Often, rooftop PV installations require penetration through the roof system. Roofing
contractors understand how to properly secure equipment on rooftops, know how to
apply flashing materials, and understand how attaching equipment to a roof system
may affect its long-term watertightness.
- Transporting material and equipment across a rooftop can damage the roof system.
The roofing contractor understands proper methods to move material and equipment
across the rooftop without causing damage.
- Many roof systems carry warranties that are issued by the roofing contractor or
the roof membrane or system manufacturer. All these warranties include provisions
that make them void if alterations are made to the system (including any attachments)
without the manufacturer's prior approval.
(February 2010)