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Geotextiles (Filter Fabric) and Roofing: Information Guide

By Roof Online Staff • Updated October 8, 2022

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Filter fabric separates ballast stone from the insulation on a protected membrane roof (Left side of picture).
Filter fabric separates ballast stone from the insulation on a protected membrane roof (Left side of picture).
Here you can see filter fabric being used to protect the EPDM membrane from the ballast stone on a ballasted EPDM roof.
Here you can see filter fabric being used to protect the EPDM membrane from the ballast stone on a ballasted EPDM roof.

1. General: For a quick overview of filter fabrics/geotextiles see this Wikipedia page. Not really anything here about the function of filter fabrics in roof construction, but it does explain what they are.

2. Safety: See this material safety data sheet for health and safety information about filter fabric at the Henry Company website. This is only an example and other products and brands may be different.

3. Technical: See “Protected Membrane Roof Systems” at Buildings.com for an explanation of filter fabric’s role in protected membrane roof (PMR) or inverted roof membrane assembly (IRMA) roofs.

4. Technical: For a quick visualization, InterNACHI shows how filter fabric fits in.

5. Technical: See how filter fabric fits into a vegetative roof assembly (often called a “green roof”) on the Whole Building Design Guide site.

6. Technical: See this product data sheet for the technical characteristics of filter fabric at the Henry Company website. This is only an example and other products and brands may be different.

8. Purchase Filter Fabric: See geotextile fabric on Amazon.