Product Description

Prime Flex 985 LX20 polyurethane foam fills voids behind and under structures. This versatile product is a two-component, low exotherm polyurethane foam used to fill voids, stabilize soil and underseal concrete slabs. Its low viscosity (270-280 cps) allows for moderate permeation effects as well. This formulation has double the expansion capacity of Prime Flex 985 LX10. It has been independently tested and certified to meet NSF/ANSI Standard 61.5 for contact with potable water.

We also produce Prime Flex 985 LX20 Fast, which has the same features but with much faster reaction times. It reacts in 12 seconds versus 68-70 seconds and reaches full rise at 65-85 seconds versus 6-12 minutes.

Recommended Applications

  • Undersealing and stabilizing concrete slabs
  • Compaction grouting of soil
  • Filling voids behind pipes, walls, manholes and other structures

Typical Areas of Use

  • Concrete slabs, including bridge approaches
  • Pipes
  • Manholes
  • Roadways
  • Sinkholes
  • Seawalls
  • Culverts


  • NSF/ANSI 61.5 compliant (standard LX 20 only, not Fast)
  • Quick set time
  • Low viscosity
  • Hydro insensitive
  • Bonds with soil and concrete
  • Low exotherm (will not self-ignite)

Completed Projects

• AK Steel – Middletown, OH
• Duke Energy – New Richmond, OH

Cured Characteristics

When cured 985 LX20 has a compressive strength of (ASTM D-1621) 4,900 p.s.f., an expansion rate of 20 times, a density of 2.5 pounds per cubic foot, and no shrinkage (ASTM D-1042 / D756).


10 gallon units
100 gallon units
600 gallon units
Standard Prime Flex 985 LX20 will be shipped unless Fast is specified.


Made in the U.S.A.

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