Why It’s a Great Idea to Repair the Manhole Chimney Before Relining a Manhole

Manhole relining is a common process that is used all over the world. You may be considering relining a significant number of manholes in your sewer system. It will be a great investment in the functional longevity of the manholes. The savings from reducing I and I in the manhole can often pay for the cost of the relining. As you design your strategy, don’t fail to consider all the factors like, adjusting the manhole frames and lids before lining the manholes.

For a manhole that is a candidate to be repaired, there are typically three rehabilitation options: cured-in-place pipe (CIPP), spray- or hand-applied polymer linings or cementitious mortar linings.

Before even choosing a rehabilitation product, however, the structure needs a proper condition assessment. NASSCO has developed a Manhole Assessment Certification Program (MACP) as the North American Standard for manhole defect identification and assessment.

As a professional working with manholes every day, You know the biggest problems are usually located at the chimney section of the manhole structure.

The chimney section represents about ten percent of the manhole structure, but it is the site of about ninety percent of the structural and leakage issues. This stands to reason, as there are usually a lot of horizontal joints in the chimney. Groundwater is usually present around the chimney section of the manhole. There is a significant amount of impact loading as traffic crosses the manhole frame and lid. The ground moves as frost comes and goes, shifting the manhole frame, and causing structural failures.

If the chimney structure fails, your liner will fail. Since ninety percent of the leakage occurs in the chimney section, you will need to get it repaired correctly. All factors considered, The chimney section of the manhole requires some strategic reworking before you invest in that expensive relining project.

Consider upcoming paving projects that will necessitate adjusting the manhole frames and lids. It will be best to do the manhole linings following paving and manhole frame and lid adjusting.

Looking at the options for adjusting your frames and lids and rebuilding the manhole chimneys will reveal a few obvious winners. Start by identifying a method that has a good specification so you can get good quality, repeatable results every time.

We love the Mr. Manhole method because of its structural integrity and leak stopping design.
So examine the manholes in your sewer system and consider all the factors as far as timing of the repairs, select a great Chimney rebuild option, Select your best lining option, plan your schedule for each phase of the project, and get the project rolling.

It is very likely that your return on investment, over time, will exceed your project cost.