Ballasted vs. Penetrating Roof Solar Mounting A Clear Comparison
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When planning a rooftop solar project, choosing the right mounting system is a key factor for long-term performance and safety. The two most common options are Ballasted (non-penetrating) and Penetrating solar mounting systems. Each offers distinct advantages and limitations depending on your roof type, structural capacity, and installation goals.
This article breaks down the pros and cons of both systems to help you make an informed decision.
What is a Ballasted Mounting System?
Ballasted mounting systems use weight—typically concrete blocks—to hold solar panels in place, without penetrating the roof surface. They are mostly used on flat roofs.
Pros:
No Roof Penetration: Ideal for maintaining the waterproof integrity of the roof.
Fast Installation: No drilling or sealing means faster setup and lower labor costs.
Easily Removable: Great for leased buildings or temporary installations.
Simplified Permitting: In some jurisdictions, non-penetrating systems face fewer regulatory requirements.
Cons:
Heavy Load: May not be suitable for roofs with limited load capacity.
Wind Sensitivity: Requires more ballast or additional anchoring in high-wind areas.
Limited Tilt Angles: Lower tilt angles can reduce solar efficiency.
Flat Roof Only: Not applicable for sloped or pitched roofs.
What is a Penetrating Mounting System?
Penetrating systems use bolts, screws, or anchors to secure the pv mounting structure directly into the roof or building substructure. They are suitable for flat or sloped roofs made from metal, tile, concrete, and more.
Pros:
Stronger Hold: Provides excellent wind resistance, especially for sloped or high-wind areas.
Lightweight System: No need for extra ballast, ideal for roofs with low weight tolerance.
Flexible Tilt Angles: Allows optimal panel positioning for higher energy output.
Broad Compatibility: Works with a wide range of roof types and materials.
Cons:
Roof Penetration Risk: Requires proper waterproofing to avoid leakage.
Longer Installation Time: Drilling and sealing add time and complexity.
Ongoing Maintenance: Roof seals should be inspected periodically.
May Require Engineering Approvals: Structural assessments may be needed depending on local codes.
Quick Comparison Table
|
Feature |
Ballasted Mounting |
Penetrating Mounting |
|
Roof Compatibility |
Flat roofs only |
Flat, sloped, and varied types |
|
Structural Load |
Heavy (requires strong roof) |
Light (direct anchoring) |
|
Installation Time |
Faster |
Slower |
|
Roof Waterproofing Risk |
Low |
Higher (requires sealing) |
|
Wind Resistance |
Moderate |
High |
|
Tilt Angle Flexibility |
Limited |
Flexible |
|
Maintenance Requirements |
Minimal |
Requires inspection |
Which One is Right for Your Project?
Choosing between ballasted and penetrating systems depends on several factors:
Roof type (flat or sloped?)
Structural load capacity
Local weather conditions (especially wind zones)
Installation timeline and budget
Waterproofing and long-term maintenance requirements
Final Thoughts
Both ballasted and penetrating mounting systems have their place in rooftop solar installations. At Xiamen TopFence Co., Ltd., we offer a wide range of solutions tailored to your specific project needs. Our business team can help you evaluate your site conditions and recommend the most cost-effective and reliable system.
Contact us today to discuss your rooftop solar project and receive a customized proposal!