Solar Components P2 Reference 5 min read Reviewed June 4, 2026 Akash Hirpara Akash Hirpara

Ballasted Racking

Ballasted racking uses weighted blocks instead of roof penetrations to mount solar on flat commercial roofs.

Definition

Ballasted racking is a flat-roof solar mounting system that uses weighted ballast blocks (typically concrete) to resist wind uplift instead of roof penetrations. Common on TPO/EPDM commercial rooftops to preserve roof warranty.

Key Takeaways

  • Ballasted racking = non-penetrating flat-roof solar.
  • Concrete or steel weights resist wind uplift.
  • Pros: no penetrations, fast install. Cons: structural capacity needed.
  • Not suitable for HVHZ (high-wind zones).
  • ASCE 7-22 wind analysis required for ballast sizing.

Frequently Asked Questions

4 commonly searched questions about Ballasted Racking.

What is ballasted racking?
Non-penetrating flat-roof solar mounting using concrete or steel ballast blocks for wind resistance. Common on commercial TPO/EPDM rooftops.
Pros and cons?
Pros: no roof penetrations, preserves warranty, faster install. Cons: requires structural capacity for ballast (typically 4–8 psf), limits tilt angle (typically ≤10°), not allowed in high-wind zones (HVHZ).
How is ballast sized?
Per ASCE 7-22 wind uplift analysis. Site-specific wind speed, tilt, GCp coefficients, roof zones. Typical 3–10 psf for low-wind sites; can't be used in HVHZ.
Major brands?
Unirac SunFrame, IronRidge BX-System, Schletter Carolina, RBI Solar, K2 Systems.

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