Stopping Infiltration through the Manhole Grade Adjustment Area (Chimney to Frame)

In manholes, the joints in the grade adjustment area (chimney to frame) inevitably deteriorate with impact loads and thermal expansion / contraction, which results in infiltration. One leaking chimney frame can introduce millions of gallons per year, with treatment costs that can exceed $10,000 annually; soil erosion also leads to costly pavement damage. Installing chimney seals, new and rehab, pays annual dividends.

Achieving a long-term seal requires accommodating for inevitable movement; mortared joints fail under such conditions. Achieving a long-term bond with flexible coating systems is also a difficult challenge; seasonal temperature extremes can take their toll on adherence because of differential expansion / contraction from the manhole materials.

An easy, reliable, permanent solution is Trelleborg's FlexRib manhole chimney seal. Trelleborg’s patented Waveband technology reliably compresses the rubber FlexRib seal against the frame casting and the manhole cone in order to achieve water tightness without relying upon bonding. The FlexRibs readily absorb joint movement without compromising the seal. 

For all of these reasons and more, every manhole chimney should be sealed with a flexible chimney seal. To discuss your specific needs in more detail, or to arrange a lunch & learn, please contact Grant Whittle at [email protected].