What Is Necessary For Manhole Rehabilitation Success? Correct Application, Use Of Manhole Rehab Technologies

By Gerhard “Gerry” P. Muenchmeyer, P.E., NASSCO Technical Director | October 2011, Vol. 66 No. 10

Haessig: Our primary focus is on internal and external mechanical manhole frame chimney seals and internal manhole barrel joint seals, plus a wide variety of manhole related products including applied chimney seals, chemical grouts, exterior joint wraps, cover vent hole plugs, inflow dishes and lightweight plastic manhole grade adjustment rings.

Kiest: We furnish the universal, stretchable, one-size-fits-all CIPMH (cured-in-place manhole) system.

Johnson: Our core product is the structural polyurethane, SprayWall. We also offer two elastomeric polyurethanes, SprayShield Green I and SprayShield Green II for corrosion protection (non-structural).

Warren: One hundred percent solids, zero VOC structural high build epoxies which are applied with a patented solvent free spray system making the process much safer to use in confined spaces.

When products are selected it is important to understand how each product is applied and what level of surface preparation is required for the host structure. Product application is typically by hand spray, spin casting, liner insertion or hand applied.

The cleaning and preparation of the host structure, however, becomes one of the most important applicator work items. Existing manhole structures can exhibit defective conditions that will affect the installation and longevity of the product. Defects can include such categories as structural, maintenance, construction and miscellaneous. Defects such as water leakage must be temporarily stopped, partially missing walls may need to be structurally rebuilt, corroded or soft materials must be removed to underlying sound base material and corroded or broken components must be removed and in some cases replaced.

The level of cleaning and surface preparation becomes significantly more important when applying those products that are designed to bond to the existing manhole structure.

How important is structure preparation for your products? What preparation do you recommend?

Shook: Permacast cement liners are structural by themselves and they adhere well to existing masonry and concrete substrates after pressure washing to remove laitance and contaminates. Cor+Gard coatings adhere extremely well over our own Permacast cement liners which provide the structural value of a composite. Primers are used over new, precast concrete.

Buyer's Guide