Rooftop and Ground Mounting for Commercial Solar

The mounting structure holds the panels at the right angle for the life of the system, through wind, rain and heat. It is as important as the panels themselves, and the choice between the roof and the ground depends on the site.

This guide explains the two options and what we check before recommending one.

Key takeaways

• Rooftop mounting uses space you already have; ground mounting needs open land.
• The roof must carry the weight and the wind load of the structure.
• Structures should be hot-dip galvanised or otherwise protected against corrosion.
• Access for cleaning and maintenance is part of the design.

Rooftop mounting

On a flat concrete roof the panels are usually mounted on steel structures tilted towards the sun and fixed to the roof or weighted down, depending on the roof and the wind. On a sheet-metal roof, rails are fixed to the roof sheets or the purlins with clamps made for that sheet.

• The roof must be strong enough for the weight of the panels and the structure.
• Fixings must not spoil the waterproofing, so they are sealed or placed on pads.
• Panels should not be shaded by parapets, water tanks or neighbouring buildings.
• Walkways and spacing leave room for cleaning and repair.

Ground mounting

When the roof is too small, weak or shaded, the panels can be placed on structures on open land, usually on concrete or driven foundations. A ground system is easier to reach and to clean, but it needs land, fencing and longer cables, and the ground must be level and well drained.

Rooftop or ground?

We recommend the roof where it has enough usable area, because it uses space that is otherwise wasted and keeps the cables short. Ground mounting is chosen where the roof cannot take the system or where a larger plant is wanted.

What we check on site

1. The roof type, its strength and its waterproofing, or the land, its levels and its drainage.
2. Shade at different times of day.
3. The wind exposure of the site.
4. The route for the cables and the place for the inverter.

When to call us

Send us your site details or ask for a visit, and we will recommend the mounting that suits it. Use the quote page, see our commercial solar solutions, or look at the mounting structures we supply.