Solar Mounting Structures: Elevated vs Flush, Steel vs Aluminium

The structure is often the last thing people think about, and the first thing that fails in a storm. We’ve seen whole rows of panels lifted by strong winds because the frame was bolted to a weak parapet. A good structure isn’t the place to save money.

Flush-mounted vs elevated

Flush or low structures sit close to the roof surface. They’re cheaper and catch less wind, but panels run hotter and the space under them is lost.

Elevated structures raise panels well above the roof, often over the water tank or stair room, or high enough to walk under. They keep the roof usable, reduce shading from tanks, and let air cool the panels. They need stronger design for wind.

Material choices

• Hot-dip galvanised (HDG) steel: strong and long-lasting when properly galvanised. Common for elevated structures.
• Pre-galvanised or painted mild steel: cheaper, but cut edges and welds rust over a few monsoons if not treated.
• Aluminium: light and rust-free, popular for flush and low structures. Thinner sections need careful design.

Wind is the main threat

Large panels act like sails. Each panel is roughly 2.5 square metres, so a row of ten is a big surface. Elevated frames especially need solid anchoring into the roof slab or beams, proper cross-bracing, and a design that considers your area’s wind speeds.

Bolts and clamps

Use stainless steel bolts and clamps made for your panel’s frame thickness. Cheap bolts rust and loosen. Wrong clamps can crack the panel glass when tightened.

Don’t damage the roof

Anchoring into the slab means drilling. Holes must be sealed properly, or you’ll find leaks in the first monsoon. Ask the installer how waterproofing will be handled.

Check after storms

After a major storm, look for loose bolts, bent rails or shifted panels. Tighten early before small movement becomes damage. More in our monsoon guide.