Key considerations when choosing a roof hook for your solar panel installation 

Key considerations when choosing a roof hook for your solar panel installation 

When it comes to technical solar products such as roof hooks, price is important — but only in combination with performance.  

These seemingly simple components are crucial to the stability, efficiency and longevity of solar panel installations. They secure solar modules to rooftops, ensure structural integrity, and protect from environmental stressors.  

For roof hooks, the main performance indicators are strength and watertightness. These features directly impact the overall system's durability and cost-effectiveness. It is also important to consider how the roof hook connects to the roof structure.  

The Renusol RH1 Roof Hook has undergone rigorous testing to ensure water tightness and load capacity. These attributes, validated by stringent European standards, are integrated into our PV-Configurator tool for precise project planning.  

In this article, we will explore the essential considerations when choosing a roof hook and why the RH1 Roof Hook is a superior choice… 

 

1. Watertightness

Watertightness is critical for maintaining roof integrity, particularly under solar installations. The RH1 Roof Hook has undergone watertightness tests in line with MCS 012 guidelines. 

The Microgeneration Certification Scheme (MCS) 012 guidelines specifically address the watertightness and weatherproofing of roof-integrated solar photovoltaic (PV) systems and related components, such as roof hooks. These guidelines not only focus on direct water resistance but also consider long-term performance and durability, ensuring certified products are both safe and resilient over time in the face of changing environmental conditions. 

 For a product like the RH1 Roof Hook, passing the MCS 012 watertightness test is a crucial validation of its reliability in protecting the roof from water ingress. This certification ensures the product meets stringent requirements for preventing water ingress, protecting the roof structure and maintaining durability even under harsh conditions, such as heavy rain, snow and wind. 

 

2. Strength and load capacity

Strength is also a decisive factor in roof hook performance.  

The RH1 Roof Hook's exceptionally high load capacity — 25% higher than Renusol's previously strongest model — provides a critical safety buffer. In scenarios where structural calculations are not performed, stronger hooks reduce the risk of tile breakage under high wind or snow loads. This added strength minimises deflection, preventing load transfer to roof tiles and significantly lowering the likelihood of damage. 

The roof hook's load capacity values are derived through rigorous testing processes, including in-house evaluations, third-party static calculations and external certifications. One such certification is the ETA-23/0814 from the European Technical Assessment. This certification is a hallmark of excellence, confirming the product's high static load capacity and ensuring compliance with the highest building product standards across the EU. 

 Of course, cost is also a factor. However, it is important to note that a higher load capacity does not necessarily mean a higher cost overall.  

To illustrate, let us consider a 14-kW solar project on a 35° pitched roof with a rafter distance of 60 cm, situated in Snow Load Zone 1 in Germany (low snow load). Using the RH1 Roof Hook, the installation would require 60 roof hooks. By contrast, a roof hook with half the load capacity would necessitate 108 hooks. 

The increased number of hooks translates to an additional installation time of approximately 5.6 hours, assuming 7 minutes per hook. With labour costs averaging at €50 per hour, this results in an extra €280, or €20/kWp, solely for installation labour. This calculation demonstrates that choosing a lower-cost, lower-capacity hook can result in higher overall costs due to increased labour requirements. 

 

3. Connection method

Roof hooks differ in how they attach to the roof structure. Some hooks are screwed directly into rafters, whilst others are hung behind battens. Hooks connected via battens often transfer snow loads to roof tiles, depending heavily on the tile's integrity. This can be problematic, especially on older roofs where tiles may have weakened over time. 

Furthermore, transmitting wind loads through battens to rafters presents challenges. The structural integrity of this connection depends on factors like nail quality, which are often undocumented. These uncertainties complicate static calculations and heighten the risk of structural failure. 

The Renusol RH1 Roof Hook avoids these pitfalls with a robust, secure screw connection to rafters, ensuring reliable load transmission and long-term performance. 

 

RH1 Roof Hook: the superior choice 

Thanks to its extraordinary load capacity, the Renusol RH1 Roof Hook drastically reduces the number of components needed for installation — setting a new benchmark in solar mounting systems. This not only cuts down on labour costs but also enhances safety and reliability. Its universal design allows for flexible configurations, whilst the adjustable base plate and arm ensure a precise fit, even on uneven roofs. 

At Renusol, our commitment to supporting our customers extends beyond product quality. Our free PV-Configurator 3.0 tool streamlines project planning, offering detailed assembly plans, structural calculations and cost breakdowns in just a few clicks. Available in 10 languages, the tool empowers installers worldwide, reducing planning time and increasing installation efficiency.  

For personalised assistance or to discuss your next PV project, Renusol's experts are ready to help. Contact us today to find out more about the RH1 Roof Hook and our other roof-mounting solutions.