California Department of Transportation

Roadside Management Toolbox


Fiber Weed Control Mat Fiber Weed Control Mat Under Sign

What is This Treatment?

Weed Control Mat (Fiber) comes in roll form and is composed of synthetic polyester fibers spun tightly together to prevent weed growth by blocking sunlight, yet still allows water percolation for drainage. The mat is made with 100% recycled drink bottles. Weed Control Mat (Fiber) is available in black or grayish green colors. Rolls can also be ordered with pre-punched post designations to assist in fast, easy installation.

The PowerPoint Presentation on Weed Control Mat (Fiber) below illustrates some key points regarding design and installation.

Fiber Weed Control Mat Presentation

When to use this Vegetation Control?

Weed Control Mat (Fiber) is effective to control weeds growth under guard rail, thrie beam barriers, cable barrier, or sign posts. This treatment may be used as an alternative to vegetation control (minor concrete) on new installations of guardrail or thrie beam barrier. Weed Control Mat (Fiber) requires a semi level, compacted sub base free of debris and minimal vegetation.


  • Available in rolls from 1 foot to 6 feet in width.
  • Available in rolls up to 250 feet in length.
  • Long lasting and durable - will not break down under UV exposure.
  • Frequently less expensive than hard surface treatments.
  • Excellent for use around existing sign posts, light poles, camera poles, etc.
  • Replacement and repairs easily accomplished by Maintenance crews.
  • Simple to remove, if necessary.
  • Can safely be placed in a landfill.
  • Allows infiltration of stormwater runoff.
  • Fire retardant.


  • Not recommended for areas with high winds and sandy soils as this treatment may lift from the ground surface.
  • Specialized stakes are available to secured properly in windy areas.
  • Application beneath existing guardrail and sign posts is more labor intensive than new installations.
  • Not recommended directly along the road edge in areas that receive snowfall as the fabric may be damaged snow removal equipment.
  • Post penetrations must be sealed with calking per the manufacturer's specifications to prevent weed growth.
  • When applied to guard rail along very sharp curves, additional cutting and seaming may be required.

Specifications and Details:

Nonstandard specifications and details are available from the Caltrans Intranet at the following address:

If you are NOT a Caltrans employee, and you need these specifications and details for consultant design work, please contact your District Landscape Architect to get a copy of these files.


Updated: June 1, 2015