No gap/insufficient gap between solar panel and roofing

A clear gap between solar water heating or PV panels and roofing allows effective rain washing of the roof surface (and occasional manual washing) and avoids retention of moisture and potential corrosion. With PV panels, overseas research also indicates that a clear air gap can lead to lower module temperatures and optimal generation output.

The Acceptable Solution for solar water heaters, G12/AS2, allows collector panels to be directly fixed to the roof cladding. Metal roofing manufacturers, however, recommend a 100 mm gap between the panel and the roof for both PV and solar water heating panels.

Causes

Gap blocked with roof debris

Incorrectly installed panel 

Listed under: water heating, solar water heating, Roof, moisture, durability, corrosion

Cause

Gap blocked with roof debris

Repair

  • clean the space between the panel and roofing annually – 6-monthly if surrounded by trees. If the debris includes leaves and twigs from nearby trees, ensure the trees are trimmed so that they do not put the solar panels in shadow

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Cause

Incorrectly installed panel 

Repair

  • call an experienced installer to disconnect the panel and reinstall it on taller brackets to lift it clear of the roofing. Check for damaged roofing and repair as necessary

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