ZSI-Foster has designed rooftop support systems that utilize 100% recycled rubber that qualifies for LEED credits and meets the Buy America Act. The units are resistant to extreme temperatures and can withstand the year-long sun and hot temperatures Hawaii has. The rubber also helps with dampening the sound and vibration that equipment can generate. Combining the Cush-A-Block with Unistrut channel, rollers, raised channel and crossbeams gives technicians a complete line of options to support your HVAC, plumbing or electrical equipment needs.

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Catalog / Product Literature:
ZF Rooftop Flyer 6-17.jpg

Catalog: Cush-A-Block

Cush-A-Block, a rooftop support block, provides a support for gas piping systems, electrical conduit, HVAC equipment, and other applications such as:

  • Solar Racking
  • Pipe & Conduit supports
  • Duct supports
  • HVAC supports
  • Cable Tray Systems
  • Air Conditioning supports
  • Roof Walkway supports


  • 100% recycled rubber
  • LEED Certifiable
  • Meets the Buy America Act
  • American Reinvestment Recovery Act (ARRA)
  • independent Laboratory Tested
  • Resistance to freeze and thaw
  • No deteriorations
  • All four corners are coated with highly visible safety orange for maximum visibility
  • Dampens vibrations
  • compatible with most rooftop materials



  • Material- 100% recycled rubber, UV resistant

  • Base Area = 33.1 Sq. In. (for use in bearing calculations)


Model No.HeightWidthBase LengthWeightUniform Load Capacity (lbs)*
Standard Base


(101 mm)

5"10- 7/8"4.80 lbs2,500



The channel for Cush-A-Block support assemblies includes a variety of options. Strut can be made in special lengths, finishes, and alloys, including:

  • Aluminum
  • Stainless Steel (304 & 316)
  • Unistrut Defender
  • Zinc Trivalent Chromium
  • Pre-Galvanized
  • Hot Dipped Galvanized



Rooftop supports have been tested by an accredited independent laboratory to the following:

  • ASTM D575 Method B- Modified- Compression/Deflection
  • ASTM D1171 Modified- Ozone Resistance
  • Freeze/Thaw Envrionment Simulation