May 8, 2024

Penetrating vs. Non-Penetrating Rooftop Guardrails

When it comes to rooftop safety, you’ve got two main options: penetrating or non-penetrating systems. Penetrating systems anchor fixtures directly into the building, like guardrails or fall arrest anchors. Basically, if you’re drilling into the surface, that’s a penetrating system.

Non-penetrating systems use counterweights or weighted anchor points, keeping things stable without harming the roof. Each approach has its pros and cons, so it’s important to choose the safest and most effective option for the job.

Why Non-Penetrating Rooftop Guardrails Became Popular

Before counterweighted guardrail systems existed, guardrails had to be attached to existing structures. On rooftops, this meant drilling into parapets or rooftop decks. However, older buildings or those lacking structural drawings often presented uncertainties about their ability to support guardrails safely. For example, some parapets contain wooden materials that could be prone to rot, creating a dangerous false sense of security.

Additionally, attaching guardrails often introduced the potential for leaks due to the holes drilled into the roof structure or parapet. Penetrating systems also required custom design, which involved significant costs for engineering. Installation of penetrating systems was also complicated, often requiring the opening of roof areas and involving lengthy installation times.

Non-penetrating systems emerged as a solution to these issues. Using weighted bases or counterbalances, they provide fall protection without compromising the roof’s integrity. They offer a safer, more versatile, and less intrusive approach to rooftop safety.

Factors to Consider Before Penetration

To penetrate or not to penetrate. It’s actually not a simple question, with a few things to consider: roof type, safety compliance, cost, and potential future changes need to be considered to decide between a penetrating or non-penetrating rooftop safety system. In fact, there are 7 primary factors. Let’s take a closer look.

1. Building Structure and Roof Type

  • Roof Material: Understanding the type of roofing material (metal, EPDM, TPO, PVC, etc.) is crucial. Penetrating systems might not be suitable for certain materials.
  • Roof Condition: The existing condition of the roof can affect the choice. A deteriorating roof might be better suited for non-penetrating systems to avoid further damage.
  • Roof Slope: Flat roofs can accommodate both systems, but sloped roofs might be more suitable for penetrating systems for better stability.

2. Safety Requirements and Compliance

  • OSHA/Local Regulations: Local and federal safety regulations might mandate specific types of systems.
  • Load Bearing Capacity: Both systems have weight requirements, but penetrating systems tend to be lighter. Understanding the load-bearing capacity of the roof is crucial.

3. Installation and Maintenance

  • Installation Complexity: Penetrating systems often require more complex installation, which could mean longer downtime and higher costs.
  • Maintenance Requirements: Non-penetrating systems might require more frequent adjustments or rebalancing, especially if contractors have moved any materials while conducting rooftop work. Some systems are easier to move than others.

4. Durability and Weather Conditions

  • Weather Resistance: Non-penetrating systems might be more prone to being displaced or damaged in high winds or heavy snow loads. It is always important to check with local requirements in regards to weather concerns.
  • Corrosion Resistance: The materials used should be resistant to corrosion, especially for penetrating systems where the integrity of the roof might be compromised. Typically finishes include galvanized, powder-coated steel, or mill-finish aluminum.

5. Cost

  • Installation Costs: Penetrating systems might have higher upfront costs due to the need for anchors and more complex installation.
  • Repair Costs: Repairs to penetrating systems can be more expensive due to the need to fix potential roof damage.

6. Flexibility

  • Portability: Non-penetrating systems are generally easier to move or remove, which might be beneficial if the roof setup changes frequently or if a temporary solution is needed.
  • Modularity: The ability to adapt or expand the safety system in the future should be considered, as non-penetrating systems might offer more flexibility.

7. Aesthetic Impact

  • Some building owners might be concerned about the visual impact of the safety system. Non-penetrating systems often have a lower profile.

Penetrating vs. Non-Penetrating Rooftop Guardrails

Penetrating Rooftop Guardrail Systems: Pros and Cons Pros:


  1. Stability: Penetrating systems provide robust and stable safety, particularly on sloped roofs.
  2. Permanent: They offer a durable, long-term solution when correctly installed.
  3. Lower Profile: Penetrating systems often have a lower visual impact on the building.


  1. Potential for Leaks: Drilling into the roof introduces potential leak points.
  2. Structural Concerns: Older or unknown roof structures might not be suitable for penetration.
  3. Installation Complexity: Installing penetrating systems is often complex and time-consuming.
  4. Engineering Costs: Custom designs typically require professional engineering, increasing costs.

Non-Penetrating Systems: Pros and Cons


  1. No Roof Damage: Non-penetrating systems do not compromise the roof’s integrity.
  2. Quick Installation: They are easy and quick to install, minimizing exposure to fall hazards.
  3. Versatility: These systems are portable and easily reconfigured.
  4. Cost-Effective: They eliminate the need for custom engineering and potential leak repairs.


  1. Less Stable: Non-penetrating systems might be less stable in extreme weather conditions.
  2. Visual Impact: The counterweight bases might be more visually intrusive.
  3. Maintenance: They may require more frequent adjustments or rebalancing.

When choosing between penetrating and non-penetrating rooftop safety systems, it’s important to consider the factors and the pros and cons we’ve covered here to ensure both safety and functionality. We prefer non-penetrating systems whenever possible, but sometimes they just aren’t an option. In those cases, we collaborate with customers and roofing companies to ensure that any roof penetrations are professionally sealed to minimize the risk of leaks.

W.S. Safety specializes in providing tailored safety solutions that meet and exceed safety standards. Our non-penetrating guardrail systems are quick to install, leak-free, and adaptable to various rooftop configurations.

Let us Help You Decide

Contact W.S. Safety today to discuss your rooftop safety needs and get a tailored proposal for your building. Protecting your rooftop has never been easier or more effective.

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