PV Panel Installation on Metal Roofs: Weight Load Considerations

SUSTAINABLE TECHNOLOGIES – including solar PV systems – are playing important roles in helping to produce low carbon and energy efficient buildings.

While investing in a solar PV system may seem like a straightforward decision for sustainability, you must consider the condition of your metal roof. The ideal scenario is that the lifespan of your roof aligns with the estimated 25-year life cycle of the PV system. If the roof has a shorter lifespan, it is recommended to replace or refurbish it prior to installing the PV panels to avoid future complications.

Weight Limitations

The structural integrity of your roof must be considered when planning the installation of a PV system, including the extra weight that the panels will bring. The average commercial solar panel weighs 22kg, meaning that for a 2,000m² building, there will be an additional 22 tonnes of weight. The fixing method must also be taken into account, as a ballasted system, for example, will bring additional weight to anchor the array to the roof.

Replacing your roof is the best way to ensure that it is structurally sound for the extra weight from the PV system, but it is not the most sustainable option. The cost, complexity, and disruption of a new roof, along with the carbon footprint from the extraction and transportation of the new metal, must be taken into account. Repairs may be a cost saving option, but they do not resolve all roof issues and may end up being a waste of your time and money.

Refurbishing the roof by oversheeting – placing new metal sheets over the existing roof – is another option for you to consider. However, this will add significant weight to your roof. For example, the 2,000m² roof will gain approximately an additional 30 tonnes.

Lightweight Refurbishment Solution

With weight loading in mind, Sharmans offers two lightweight roof refurbishment systems:

• Delcote^® – The Full Roof Coating

– Backed by an industry leading 25 or 10 year product guarantee (Dual/Single Coat)

• Seamsil^® – The Cut Edge Corrosion System

– Backed by an industry leading 15 year product guarantee

These market leading metal roof coating systems refurbish the existing roof to extend its life cycle. They offer a lightweight refurbishment solution, only taking into account the additional weight of the PV system and its components when considering structural loading.

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