Open trench excavation is the traditional and previously most common method for sewer lateral repair or replacement in the Twin Cities area. This technique involves digging a trench to manually install each section of pipe. It is typically used for addressing issues such as collapsed pipes, severely broken pipes, and significant root blockages.
Compared to trenchless sewer repair, the open trench method is generally more expensive. This is due to the increased time, extensive excavation, and subsequent restoration required. Additionally, it often necessitates the removal of street and sidewalk pavement, further driving up the costs. Despite these higher expenses, open trench excavation is sometimes the only viable solution when trenchless methods are not feasible. Below, we outline the scenarios that may necessitate the use of open trench excavation.
Why Do We Sometimes Have to Use Open Trench Excavation?
The open trench excavation method is necessary in certain situations for one of three main reasons:
- A New Sewer Pipe Cannot Be Pulled Through: This issue is primarily mechanical. Sometimes the fastening materials around the joints of an existing sewer line are too thick and strong, or the coupling sleeves won’t break during “pipe pulling.” As the couplings get stuck, the pressure causes them to stack up down the line. This increased tension stresses the equipment, causing the pulling ram to stall. In extreme cases, concrete and other fixed surfaces may be lifted, broken, or stalled underground. Consequently, we are unable to pull a new pipe through, necessitating manual excavation of the area.
- To Ensure Safety in Areas Surrounded by Dangerous Utilities: In some cases, the work takes place in areas where numerous utilities are located close to the sewer line, such as water, electric, gas, or fiber lines. Due to the hazardous nature of these environments, open trench excavation is preferred over trenchless sewer repair. To prevent serious underground accidents, we manually dig in specific areas to safely expose the pipes.
- Engineering and Design: Finally, open trench excavation may be necessary due to the engineering and design of the sewer line. For instance, we might discover a sewer line belly once we begin repairs. Sewer line bellies typically require open trench excavation to fix. This process involves removing the existing sewer line, digging deeper, and laying an aggregate base to support the pipe, ensuring the proper slope and flow of the line.
Do You Need Open Trench Excavation?
A skilled engineer can assess whether open trench repair is the best solution for your property or if trenchless repair might be more suitable. The engineer should clearly explain why open trench excavation is necessary and inform you of any changes to your estimate.
M& B Services is the most trusted sewer contractor in Minneapolis and the St.Paul. Our team of experienced plumbing professionals will help you make informed decisions with confidence. If you need sewer repair and are unsure whom to turn to, contact us for a survey of your project area. With over 10 years of experience in sewer line repair—both traditional open trench and trenchless—you can rest assured your sewer repair job will be done right.