With manufacturers offering “easier” non-flashed solar mounting, it’s important to understand the inherent risks.
Ryan Winkle of RD Winkle Roofing and Solar has repaired dozens of roofs in Southern California with leaks caused by solar installation, despite the region’s arid climate and years of drought conditions. “We don’t even know how many roofs are currently leaking because the solar attachments weren’t correctly flashed,” he says.
A new white paper, “Flashing Requirements for Roof-Mounted Solar Arrays,” examines the issues homeowners, contractors and solar finance companies should understand prior to selecting or approving attachments for composite roofs.
Improperly installed roof attachments can lead to major water, rot and mold damage. Often the problems develop slowly or remain hidden for years, until homeowners face expensive repairs and remediation. Contractors or solar financiers installing systems that don’t comply with international building codes and roof manufacturers specifications may find themselves liable for significant repairs.
The white paper identifies the minimum requirements in International Building Code (IBC) and International Residential Code (IRC) for preventing moisture penetration of the roof plane. The white paper also outlines requirements set forth by leading composite shingle manufacturers related to solar PV systems. No major shingle manufacturer endorses or approves non-flashing based solar mounting systems.
Another consideration the white paper examines is the reliability of lab-based testing data. While non-flashing based mounting manufacturers cite claims that sealants can be effective for 25 years, the tests reflect ideal lab conditions, not real-world applications. Typical solar installations involve aged shingles, dirty and uneven surfaces, and sealant that may have been stored or applied in too cold or too hot conditions often seen on rooftops.
Importantly, years of thermo-cycling and snow loading can substantially accelerate sealant degradation compared to a lab environment.
Furthermore, actual installations present challenges such as mounts that straddle shingle tabs of different thicknesses, and unused pilot holes that occur when finding rafter locations. Without adequate flashing, these conditions impose a significant burden on the sealant and increase the likelihood for cracking and water penetration.
Reliance on caulking to protect the integrity of a home’s roofing system invites expensive problems down the road for both solar contractors, finance companies and homeowners.
A properly flashed and installed solar array is a valuable, long-term investment. All involved parties should be fully informed of the standards for flashing roof attachments, as well as the potential consequences of non-standard approaches.
Read the full paper here: Flashing Requirements for Roof-Mounted Solar Arrays