Living Roof Calculator

Calculate green roof structural loading, stormwater retention capacity, thermal performance, and cost for extensive or intensive systems.

Roof Area (sq ft)

Growing Media Depth (in)

Saturated Media Density (lb/ft³)

Drainage Layer Weight (psf)

Annual Rainfall (in)

Roof Slope (degrees)

Existing Roof Dead Load (psf)

Tab to move between fields

Green Roof System Weight (psf)

34.3

Total Dead Load (psf)49.3

Storm Retention (gal)2,449

Annual Retention (%)60.9%

Annual Retained (gal)27,325

Added R-Value2.8

Energy Savings ($/yr)$250

Roof TypeExtensive (sedums, low maintenance)

Estimated Cost$30,000

How to Use This Calculator

Enter Roof Area in sq ft and Growing Media Depth in inches (2–6 in extensive, 12+ in intensive).
Enter Saturated Media Density in lb/ft³ and Drainage Layer Weight in psf.
Enter Annual Rainfall in inches, Roof Slope in degrees, and existing Roof Dead Load in psf.
Review Green Roof System Weight and Total Dead Load — verify structural capacity is not exceeded.
Check Annual Stormwater Retention, R-Value Addition, and Annual Energy Savings.

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