Internal Manhole Sealing System

World’s Most Cost Effective, Practical, System for Permanent Rehabilitation, and Repair of Manholes.

SANI-TRED® INTERNAL MANHOLE system not only seals manhole chimneys but strengthens them at the same time. SANI-TRED® manhole seal products maintain permanent strength, and flexibility when fully cured with its FLEXIBLE PENETRATION® and PERMANENT ELONGATION® technologies. SANI-TRED® PERMAFLEX™, (liquid rubber primer and top coating) penetrate deep into the actual pores cracks and joints of the concrete substrate to produce small "rubber sealing plugs". These capillary filled sealing plugs, or “tentacles,” that penetrate deeply in every single pore is the reason SANI-TRED® is unmatched at FUSING PERMANENTLY to the concrete surface of an internal manhole and holding back the relentless forces of negative ground water pressure that other products could not possibly attempt.

  • Manhole Vacuum Testing Results: (Vacuum Test Results; at 29.9" Hg for 110 hours leak free) (independent Testing, University of Wisconsin Milwaukee)
  • (Existing standards for a passing Manhole Vacuum test ASTM C-1244 is (12” Hg for 5 min)
  • SANI-TRED® was found to exceed the accepted minimum test by a factor of 1,300 times!
  • SANI-TRED®PERMAFLEX ™ was determined through UWM testing to have a bond, to properly prepared concrete, that is stronger than the actual concrete itself!

SANI-TRED®’s Fusion to the concrete surface allows SANI-TRED® PERMAFLEX™ to retaining negative hydrostatic pressure at the microscopic level to eliminate “weeping” before the water pressure has an opportunity to reach the Permaflex coating membrane surface, accumulate behind the main sealing membrane surface, create blisters and eventually fail as experienced with other coatings that have attempted to retain negative hydrostatic waterproofing or “TANKING”. These “tentacles” work like small, high pressure O-rings for a manhole cover seal! The tentacles anchor, lock to the concrete and protect the actual PERMAFLEX™ from ever delaminating or blistering.


SANI-TRED Manhole Sealing Advantages

  • Requires no confined entry
  • A Lifetime Seal, as permanent as the internal manhole itself (Life of the Structure Warranty)
  • Seals all Holes and Joints (Regardless of Size)
  • Trenchless, non-invasive system requiring no excavation or disturbance of surrounding areas
  • May be installed, shipped and handled year round
  • Bonds Permanently to Concrete and Cast Iron
  • Molecularly Welds to itself new-to-old at any age or stage of curing allowing easy future grade adjustment seal repairs (cures tack-free in 1-3 hours)
  • Non-Disruptive or Invasive to the community (Because of the short duration installation steps SANI-TRED® is the only system in the world that requires none of the normal traffic control of other methods)
  • Cost Effective and Practical to seal all manholes in the entire community
  • Cures to the same strength as truck tires 2,600 psi tensile
  • Maintains Permanent Flexibility with 600% elongation (endures constant heavy traffic shock)
  • Cures at any temperatures
  • Easy to Inspect, the clean bright white interior highlights even the smallest errors or leaks (showing up as dark mineral or rust streaks on the surface)
  • Permanently Waterproof • Non- Toxic • Non-Hazardous • Odor-Free   • Non-Flammable

Why is SANI-TRED® strong and able to last the life of the structure?

The manhole cover seal system starts with SANI-TRED® Permaflex, a unique ultra-adhesive, incredibly strong, permanently flexible, polyurethane based primer. Next apply LRB/TAV mixture. This is a heavy bodied, liquid rubber, plural component base product that is also so incredibly tough it is normally used to surface heavy forklift vehicle traffic areas as well as indoor basement waterproofing and commercial swimming pool sealing. This LRB/TAV base cures evenly at any thickness of application to a solid rubber as tough and strong as truck tires and bonds molecularly to the Permaflex primer. A final coat of SANI-TRED® Permaflex completes the installation.

Longevity and SANI-TRED® Manhole Rehabilitation

Old tires have been directly buried in the earth for over 100 years, unearthed, only to discover that they were in as good condition as when originally buried! SANI-TRED® is a unique form of polyurethane or artificial rubber. Polyurethanes are among the most complex molecules known to man. They are extremely flexible and completely unmatched for durablility.

Scientists have determined that the best possible environment to keep and maintain rubber products (both natural and artificial) is to keep them in a damp environment in the absence of UV exposure. Under these conditions it has been determined that natural or artificial rubber will last virtually forever without breakdown or deterioration. These are virtually the same conditions found inside a manhole.

The oldest SANI-TRED® installation, an outdoor commercial floor surface, is over 36 years old in a heavy foot traffic, UV exposure, environment with no signs of breakdown or substantial wear. This is only one of the many reasons we can so confidently make the statement "permanently waterproof manholes" and you can have confidence in that statement for your manhole cover seal rehabilitation projects.

Internal Manhole Sealing



  1. Prime with Permaflex
  2. Apply LRB-TAV Mixture Reinforcement to, Fill, Seal and Profile All Cracks & Joints Regardless of size
  3. Apply one or two Top Coats of Permaflex

This three-step process assures that every crack, hole, joint and crevice is permanently sealed. Experience has proven that a simple single application of something is usually not worth the effort it takes to apply it. By using the SANI-TRED three-step process you are triple protected and assured that all joint imperfections are filled and sealed the first time for the last time!

SANI-TRED products have passed over 20 years of field testing and research in underground water vessels such as manholes, basements, deep cisterns, waste water treatment tanks, elevator pits and swimming Pools. This field testing and research is coupled with a rigorous independent testing regimen designed By "The American Society of Testing and Materials, or (ASTM). These independent tests have proven that a SANI-TRED product manhole installations exceeds the minimum requirements for negative pressure retention in US manholes by almost ten times!

  • Negative Hydrostatic Vacuum ASTM C-1244 RESULTS 5 min. @ 12 in.
  • Negative Hydrostatic Air Pressure Rev. ASTM C-1244 RESULTS 5 min. @ 10 lbs.

Constant hydrostatic pressure from the side walls, along with heavy vehicle traffic pounding will never detach SANI-TRED products. They will not peel, blister, chip, delaminate, or detach from concrete, cast iron, concrete block, mortar, in the constant presence of negative hydro-static water pressure on  the coating's  "raw edge".


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