Terrace Garden Load Calculator
Wet soil is heavy — the biggest risk in a rooftop garden is overloading the slab. Estimate the weight you would add, in total and per square metre, and see whether it is within a typical terrace’s allowance or needs a structural engineer’s sign-off.
Shallow for herbs/sedum (10–15 cm); deep for shrubs & small trees (40 cm+).
Saturated (just-watered) weight — the worst case a slab must carry.
≈ 8,488 kg total over 20 m².
Likely exceeds a normal terrace's capacity — a structural engineer must confirm or the slab strengthened before you build it.
An awareness estimate — not a structural clearance. The ~150 kg/m² figure is a typical residential accessible-terrace live-load; YOUR slab’s real capacity depends on its design and condition. Whether a garden is safe is a structural engineer’s call — and never let a garden sit directly on the roof: it needs intact waterproofing, a root barrier and a drainage layer (see the terrace garden guide).
Related Guides — Deep-dive reading
Terrace Garden Planning
A rooftop garden is one of the most rewarding things an Indian home can grow — but a garden on a roof is a load, a moisture trap and a drainage problem before it is a pleasure. This guide puts the three real risks first — weight, waterproofing and drainage — then covers containers vs raised beds, lightweight media, plants for rooftop sun and wind, irrigation and maintenance.
RoofingOverhead Water Tank on the Roof (India): Why It's Up There, Sizing, Structural Load, Fittings & Care
The rooftop tank is what gives your taps and showers their pressure. Why height creates head, how to size it, what a full tank weighs and how to support it on the slab, materials, staging height, overflow and vent, sun and algae, cleaning access, and when to run more than one tank.
PlumbingCool Roof vs Green Roof: Which Beats Roof Heat Better?
Two very different ways to stop your slab from cooking — the cheap, light, reflective cool roof that bounces the sun away, versus the planted green roof that insulates, shades and gives you a garden. A balanced, India-grounded comparison across heat, cost, structural load, waterproofing, upkeep and co-benefits.
RoofingRelated Tools — You may also find these useful
Rainwater Harvesting Calculator
How much rainwater your rooftop can harvest in a year, in litres and kilolitres, from the roof area, your city's rainfall and roof type — with a suggested storage-tank size.
RoofingRoof Area Calculator
The true (sloped) surface area of a roof from its plan footprint and pitch, in m² and sq ft, with a wastage allowance and rough tile/sheet/coating counts — the area you actually buy roofing materials for.
RoofingRoof Cost Calculator
An indicative cost range to build a roof in India, by roof type (RCC, tiled, metal, sheet), area, waterproofing, insulation and city — total and per sq ft. A budgeting frame to confirm with local quotes.
Roofing