Module Mounting Structure
The module mounting structure is the engineered framework — rails, purlins, legs, ballast or anchors — that holds solar modules at tilt on a roof or ground, designed against IS 875 Part 3 wind loads so the array stays down and the roof stays whole.
Why it matters on an MEPF project
Wind, not weight, is the structure's real exam: uplift on tilted arrays in a storm can exceed the dead load severalfold, and every anchorage or ballast decision traces back to IS 875 Part 3 for the site's wind zone. Structures are also the corrosion frontier — galvanising thickness and hardware quality decide whether year-10 photographs show a plant or a rust archive.
On roofs, the structure mediates between plant and building: purlin-fixed rails on sheet roofs (with EPDM-sealed penetrations), ballasted or anchored frames on RCC (with the dead load checked against the slab), walkways that keep cleaning crews off modules and sheets alike. A structure certified by design, not by habit — with the calculation in the handover file — is what lenders, insurers and the next auditor expect to see.
How it's specified in practice
| Parameter | Typical / working position | Governing reference |
|---|---|---|
| Wind design | Site wind zone → uplift/anchorage per IS 875 Part 3 | IS 875 Part 3 |
| Roof interface | Purlin-fixed (sheet) / ballasted or anchored (RCC), load-checked | structural verification |
| Corrosion protection | Galvanised steel / aluminium; SS hardware | material specification |
| Serviceability | Walkways, clearances, cable management provisions | O&M-aware design |
Common mistakes
- Ballast quantities by folklore rather than wind calculation.
- Sheet-roof fixings missing purlins — held by sheeting alone.
- Thin galvanising that rusts before payback.
- No walkways, so cleaning traffic dents sheets and modules for 25 years.
Related on this site
Frequently asked
How much weight does the structure add to my roof?
Working bands: rail-mounted sheet-roof systems around the mid-teens kg/m²; ballasted RCC systems higher (ballast included). Our roof-load calculator gives the estimate; a structural check makes it a verdict.
What survives a 150 km/h storm — ballast or anchors?
Whatever the IS 875 calculation for your zone says, executed as designed. Storm losses almost always trace to structures built lighter than their own drawings — or drawings that never existed.
Standards referenced: IS 875 Part 3 · material/galvanising standards by specification