A root-resistant layer is a component intended to resist root penetration within a roof assembly. That function can be system- or product-specific. Ordinary roof covering does not automatically establish that a roof is suitable for vegetation or a planted arrangement.
An existing green roof also requires consideration of other layers and conditions of use. Ask what information is available for the system actually installed. A green upper surface in a photograph does not identify the protection or junctions present underneath it.
This explanation prescribes no green-roof assembly and makes no capacity determination. Adding or changing vegetation raises separate questions about technical assessment and applicable conditions. Retain relevant product information clearly connected to the component actually installed rather than treating a generic label as approval.
Worth asking
Frequently asked questions
Is every EPDM product automatically suitable?
That should not be assumed. Check the selected system’s actual conditions and application.
Does root resistance prove sufficient capacity?
No. They are different technical questions.