Generally, a lower-mass turf system can make the structural calculation easier, but “lightweight” does not automatically mean “suitable for every roof.”

The relevant number is the mass of the complete installed system, not simply the weight of the turf roll.

For example, a rooftop system may include:

• Artificial turf
• Underlay
• Protective mat
• Drainage layer
• Adhesive or fixing components

Water retained after heavy rainfall can also temporarily increase the load.

Therefore, the structural engineer should use the actual product data and system construction when checking the roof.

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What About Rooftop Gardens and Green-Roof Standards?

Rooftop landscaping projects may be subject to building, structural, waterproofing and drainage requirements that differ by country and municipality.

In the United States, the applicable requirements can include local building codes, structural design requirements, roof-system specifications and project-specific waterproofing requirements.

In Europe, relevant national and European standards may apply depending on the roof type and construction.

For Chinese projects, standards such as JGJ 155 for planted roof engineering may provide relevant reference for certain green-roof systems, but artificial turf should not automatically be treated as equivalent to a conventional planted roof.

The correct approach is to determine the actual roof construction and applicable local code requirements first, then design the artificial-turf system around them.