Key takeaways
- Rooftop uses space you already have and avoids land, fencing and piling costs
- Ground-mount gives freedom to size, orient and maintain the plant, and avoids old or weak roofs
- Industrial sheet roofs need a structural check, purlin-mounted structures and skylight safety mesh
- Ground-mount needs a soil test, pile foundations sized to it, fencing and drainage
- Many sites combine both: rooftop on the sound sheds, ground-mount on spare land
The short answer
| Factor | Rooftop | Ground-mount |
|---|---|---|
| Space | Uses existing roofs | Needs land (roughly 4 to 5 acres per MW for fixed-tilt) |
| Cost per kWp | Usually lower: no land, fencing or piling | Higher civil cost, but scale can offset it |
| Size | Limited by roof area and strength | Sized to need (and land available) |
| Orientation and tilt | Follows the roof | Optimised for yield |
| Structure | Purlin clamps or ballast; roof-load check essential | Piles or foundations to the soil test |
| Safety | Work at height; skylight mesh, lifelines, walkways | Ground-level work; fencing and security |
| Maintenance | Access via walkways; roof-wash systems | Easy access; vegetation control |
| Best for | Factories, warehouses, commercial buildings | Tea estates, open-access and captive plants, farms |
Rooftop: what makes a good roof
- Strength: a structural engineer confirms the roof and purlins can carry the added load and wind uplift.
- Remaining life: re-roof first if the sheets have only a few years left; removing a plant to re-roof is costly.
- Shade-free area: watch for parapets, tanks, chimneys and neighbouring buildings.
- Safety for life: skylight safety mesh over translucent sheets, lifelines and walkways for cleaning crews.
Ground-mount: what makes a good site
- Soil test first: it decides pile depth and diameter, and whether augered or driven piles suit.
- Drainage and flooding: low-lying land needs raised structures and drains.
- Evacuation: the distance to your meter or the grid connection point.
- Security: chain-link fencing, gates and lighting.
- Land rules: in Assam, tea gardens may use up to 5% of their land for solar (see our tea-estate guide).
When to combine both
Plenty of sites use both: rooftop on sound sheds near the main load, ground-mount on spare land for the rest. The two can feed the same distribution board or separate meters, depending on your connection and state rules.
Not sure which suits your site? Send us a roof photo or a land sketch and your bills.
Get a free solar quoteFrequently asked questions
Is rooftop solar cheaper than ground-mount?
Usually per kWp, because there is no land, fencing or piling. Ground-mount can be competitive at larger scale and gives more freedom in size and orientation.
How much land does a 1 MW ground-mount solar plant need?
Roughly 4 to 5 acres for a fixed-tilt plant, depending on module efficiency, row spacing and the shape of the land.
Can any factory roof take solar panels?
Not always. A structural check of the sheets, purlins and trusses is essential, and old roofs should be replaced before installation.
Why do sheet roofs need skylight mesh?
Translucent skylight sheets cannot take a person's weight. Safety mesh under or over them protects installers and cleaning crews.
Sources
- Himanta Biswa Sarma, Rewriting Assam's Energy Future, 22 Sep 2026
- PIB: MNRE notifies the revised Quality Control Order for solar photovoltaic products
This guide explains public policy in plain language for planning purposes. Rules, rates and deadlines change: confirm the current position with the notifying authority, your DISCOM and your tax adviser before you commit. Last checked 11 Oct 2026.
About the authors. Arrays Ingenieria is an ex-servicemen-led solar EPC and installation & commissioning company working Pan-India, from Assam's tea estates to industrial rooftops. Our story · Our projects
