Unruly tree roots, decades-old corrosion, continuous freeze-thaw cycles — you name it, and various culprits can cause irreparable damage to exterior pipes, including key sewer and water supply lines. Now, imagine having to tell a homeowner that you’ll need to dig a 5-foot-wide trench to replace the pipes… and they may need to backfill, reseed, and resod the entire area once you’re done.
Needless to say, most homeowners want to avoid expensive excavations and invasive construction practices by any means necessary. Fortunately, trenchless technology allows contractors to replace or rehabilitate existing pipelines with minimal disruptions to aboveground and underground infrastructure. Here’s what you need to know about today’s trending trenchless methods.
What Trenchless Technologies Are Trending?
Trenchless technology refers to a category of subsurface construction methods that requires few trenches or, ideally, no continuous trenches to repair or replace existing pipelines. First introduced as a rehabilitation technique for water pipes in the 1970s, the plumbing, construction, and civil engineering industries are now prime sources of high-demand trenchless technology.
Whether you’re a contractor seeking additional certifications in plumbing design or a business owner searching for alternatives to costly excavation equipment, you’ll want to catch up to speed on the difference between trenchless technologies — especially these trending methods.
1. Pipe Bursting
Pipe bursting is one of the most common types of trenchless technology used in residential settings. Often confused with more industrial forms of trenchless pipe installation, like pipe ramming and pipe jacking, pipe bursting is the process of physically pushing apart an existing pipe by pulling an expansion head throughout the pipeline and creating space for a new one.
The application of pipe bursting requires strength and flexibility, so it’s most commonly used with high-density polyethylene (HDPE) or fusible polyvinyl chloride (PVC) piping. In the field, you’ll see pipe bursting for either pressure or gravity pipelines, primarily for size-on-size replacements. This method will require launching and receiving pits, so minor excavation will be required.
2. Pipe Slip-lining
Compared to pipe bursting, pipe slip-lining is a type of trenchless technology in which the original host pipe is left as is. Instead of destroying the old pipeline, the slip-lining process involves “slipping” a new inner pipe — referred to as a liner or a carrier — inside the existing pipeline. The new pipe has a smaller diameter than the original one, so it can glide over any imperfections.
Slip-lining is primarily used when there is significant damage to the entire pipe, but the surrounding area is structurally sound. It’s often used to repair water pipes, sewer lines, and storm drains. The process of slip-lining causes very minimal surface disruptions; however, the smaller diameter of the new liner may cause reduced flow capacity for water and sewer lines.
3. Cured-in-Place-Pipe (CIPP)
Cured-in-place-pipe (CIPP) is similar to slip-lining, but with a much different material. CIPP involves inserting a felt or resin-coated liner inside of an existing pipeline, then using a liquid curative to harden and bond the liner to the host pipe, or curing the liner with heat or ultraviolet light. It can be used on pipe diameters from 3 to 60 inches, including sewer mainlines and potable water lines.
CIPP is one of the only truly ‘trenchless’ technologies for sewer line rehabilitation, as the process can often be completed via manholes. It allows contractors to access impacted structures without excavation or disruption to sidewalks, which is rare when servicing mainlines. Plus, CIPP keeps the current infrastructure intact, helping to extend the lifespan of original pipelines.
4. Spiral Wound Lining (SWL)
Like CIPP, spiral wound lining (SWL) uses flexible yet durable materials for sewer, storm drain, and water line rehabilitation. Instead of a curative material, the SWL process winds continuous plastic strips — typically HDPE or PVC, like pipe bursting — to form a new, continuous pipe inside of the original host pipe. The strips often feature steel-embedded ribs for extra strength.
The level of ground disruption necessary for SWL varies, as the process can be complete via manholes with no trenches whatsoever, or via launching and receiving pits with minimal excavation. What sets SWL apart from other trenchless technology used in the construction process is that it can accommodate non-round shapes and be installed around bends, even with live flow.
Why Should Contractors Leverage Trenchless Technology?
There are many reasons for plumbing contractors to utilize trenchless technology, but they all come down to one key point: these methods benefit everyone involved — business owners, homeowners, and neighbors alike. Because it requires minimal excavation, trenchless technology often condenses what could be weeks of surface disruptions into one day’s worth of work.
It’s no secret that homeowners would prefer to avoid hefty excavation equipment ripping up their front or backyards, and the neighboring houses would prefer to not have their sidewalks broken to reach the underlying infrastructure. Plus, the faster work is completed, the faster water and wastewater utilities can be brought back on for the homeowner and the surrounding community.
Not to mention, the minimal digging involved with trenchless technology allows for significant cost savings, both for homeowners and contractors who can ditch the costly excavation equipment. Likewise, with less excavation, trenchless technology offers greater contractor safety. There’s less risk of surface disruption that can cause dangerous water, mud, or landslides.
Challenges of Trenchless Technology (and How to Solve Them)
Despite their many advantages, each trenchless technology installation method will have its own challenges. By and large, their primary challenge is the unknown. While plumbing contractors utilize investigation potholes, geotechnical boreholes, and sewer or drain cameras to confirm original pipe conditions, they often only have one point of observation — and many obstacles can lurk underground.
Here’s a breakdown of the common challenges of trenchless technology, and how to proactively solve them:
- Unclear pipe conditions, like the structural integrity, existing line material, and depth of the original piping, can make it difficult to decide which trenchless technology to use. It’s wise to make several boreholes to examine as much of the pipe as necessary.
- Uncertain ground conditions, like compact soil or rock, can allow displaced soil to migrate during and after the rehabilitation process. Relief holes can be created with horizontal directional drilling (HDD) to form a void for the displaced soil to safely move to.
- Unknown repair histories, like unpredictable pipe fittings, varying pipe materials or thicknesses, and concrete joints or encasement, can impede the current repair process. In these cases, you may need to drill a rescue pit to complete the rehabilitation.
- Unspecified surrounding underground utilities, like gas lines or electrical cables, can be placed too close to the original host pipe to allow for maintenance. You must complete a risk assessment on the neighboring utilities before moving forward with repairs.
Navigate the Trenchless Industry Like a Pro
Modern trenchless technology offers plumbing contractors durable solutions for some of life’s most unavoidable problems, like cracked sewer lines or corroded water lines. Here at JB Warranties, we offer comprehensive solutions for some of the industry’s other unavoidable problems, like parts and labor protection for boilers, water heaters, tankless water heaters, and tankless water systems.
Explore our extended warranty solutions for plumbing contractors today, or schedule a meeting with a JB Warranties Representative to learn more.
Tommy Cue
Vice President of Strategic Partnerships at JB Warranties
