Open Trench Excavation: Why We May Have to Do It

Construction roadwork on street in city. Red safety sign warns a

Open trench excavation is the traditional and was the most common method for sewer lateral repair or replacement. Open trench excavation consists of excavating a trench for the manual installation of each piece of pipe. This type of sewer work is applicable to collapsed pipes, severely broken pipes, and heavy root blockages.

The open trench method is, on average, more costly than trenchless sewer repair as it requires more time, excavation and restoration to complete. In addition, open trench excavation may require the removal of street and sidewalk pavement which also increases the cost of the repair. Despite the expense of open trench excavation, there are instances where it is the only option over trenchless sewer repair. Below, we explain reasons we may have to open trench a particular location.

Why We Sometimes Have to Use Open Trench Excavation

The open trench excavation method is used for one of three main reasons:

1. A New Sewer Pipe Cannot Be Pulled Through – This reason for open trench excavation is more about the mechanics in performing trenchless sewer work. Sometimes, the fastening materials around the joints of an existing sewer line are too thick and strong—or the coupling sleeves won’t break when “pipe pulling”. As the couplings get stuck, the pressure pushes the couplings down the line where they stack up. That increased tension stresses the equipment and the pulling ram begins to stall. In extreme cases, concrete and other fixed surfaces get lifted, broken or even stalled below ground. For this reason, we’re unable to pull a new pipe through and the area around it needs to be dug up manually.

2. To Ensure Safety in Areas Surrounded by Dangerous Utilities – Sometimes, the work is done in areas where there are too many utilities adjacent to the sewer. These utilities include water, electric, gas or fiber lines. Due to the dangerous nature of these areas, open trench excavation is highly recommended over trenchless sewer repair. To prevent serious accidents from happening underground, we hand dig those areas to expose the pipes. 


3. Engineering and Design – Lastly, the need for open trench excavation can be related to engineering and design of the sewer line. For example, we may encounter a pipe with a sewer line belly after we break ground to repair a line. Sewer line bellies almost always require open trench excavation to correct. During this process, we remove the existing sewer line, dig a bit deeper, and lay the aggregate base that supports the pipe for the proper slope and line flow.


What Should You Do if You Need Open Trench Excavation?

A good engineer always knows when an open trench solution is best for your property. They will be able to walk you through “why you need it” and what changes in your estimate you can expect. Pipe Spy has been a trusted sewer contractor with a team of competent professionals to help customers make those tough decisions with confidence.  If you’re in need of sewer repair and you’re unsure what method is best for your property, call or contact Pipe Spy for a survey of your project area. Our 40+ years of experience in sewer line repair, both traditional and trenchless, make us the best people for the job.