Why Solar Panel Expansion Gaps Matter
Many solar installations in the UK are fitted with little or no gap between panels. While this might make the array look neat or maximise roof coverage, it can lead to long-term damage that affects performance, safety and system lifespan.
Solar panels are framed in aluminium, which expands and contracts as temperatures change. An expansion gap is the small space left between panels to allow for this movement without putting stress on the frame or the panel itself.
Why Expansion Happens
On a sunny day, solar panels can reach temperatures of 60–80°C, even in the UK. At these temperatures, aluminium frames expand. If panels are installed too tightly together, they press against each other and transfer stress into the panel structure.
What Happens If There Is No Gap?
- Microcracking of solar cells – reduces output over time
- Frame stress and distortion – weakens panel structure
- Seal failure – allows moisture into the panel
- Hotspots – increases risk of long-term damage
- Potential electrical faults in extreme cases
These issues are often not visible immediately but can lead to gradual performance loss and premature system failure.
How Much Gap Should There Be?
Most manufacturers recommend a gap of around:
- 10–20 mm between panels
- Sometimes as low as 5 mm if specified
The exact requirement depends on the panel manufacturer and mounting system, but panels should never be installed tightly touching.
Why Many Installations Get This Wrong
- Trying to maximise the number of panels on a roof
- Poor rail alignment forcing panels together
- Incorrect use of mid clamps
- Lack of understanding of thermal expansion
This is one of the most common quality issues seen in retrofit inspections.
Standards and Compliance
UK installations should follow manufacturer instructions and standards such as MCS (MIS 3002). Installing panels without allowing for thermal expansion may not comply with these requirements, as it introduces long-term mechanical stress and risk of failure.
How We Install Panels at Speedy Fit
- Consistent spacing between all panels
- Correct clamp positioning
- Rail alignment checked before installation
- No forced panel fitting
Our approach ensures your system performs reliably for the long term, not just on day one.
Solar Installations in Worthing and West Sussex
Speedy Fit installs solar PV and battery systems across Worthing and West Sussex, focusing on long-term reliability, safety and compliance. If you are considering solar, we are happy to provide advice and a detailed quotation.
Get a Solar Quote