Construction Methods to Eliminate Defects in Side Sewers
This section describes various methods available for repairing, replacing, or rehabilitating an existing side sewer. Every side sewer is unique and not all methods are suitable for all circumstances. It is always important to work with a sewer contractor experienced with the particular kind of construction to determine the suitability for each side sewer on an individual basis and to obtain cost estimates for the various methods as they may vary greatly for each project.
Open cut construction
This method of construction is the typical dig and replace that most people are familiar with. This is the most common method of repairing side sewers and consists of digging up the old pipe and replacing it with new pipe. Open cut may be less suitable for areas where there are significant surface improvements that a property owner wants to avoid disturbing and that are costly to replace or when side sewers are fairly deep.
This method of construction consists of inserting a new flexible pipe into the old pipe. This method requires digging an installation pit and a receiving pit at each end of the side sewer to allow for the pipe to be inserted and to make final connections at each end. This method is beneficial for sites where there are surface improvements that an owner either chooses not to disturb or that would be expensive to replace. Pipe bursting is not suitable for pipes that are no longer round enough to allow for the bursting machine to penetrate, in pipes with multiple bends, or in pipes that need to have sags corrected as the new pipe will follow the vertical alignment of the old pipe.
Cured In Place Pipe (CIPP) lining
CIPP consists of rehabilitating an existing pipe with a new pipe. A resin-soaked felt tube liner is inserted into the existing pipe, inflated to expand to the shape of the existing pipe, and then cured until the resin hardens to form a pipe within the old pipe. CIPP is also beneficial for sites where there are surface improvements than an owner either chooses not to disturb or that would be expensive to replace. The liner can be inserted through cleanouts in the side sewer and requires no other digging unless needed to install a cleanout. Since CIPP forms to the shape of the existing pipe it is not suitable for pipes that are collapsing or egg-shaped, nor can it be installed in pipes with multiple bends or in pipes that need to have sags corrected as the new pipe will follow the vertical alignment of the old pipe.
If the majority of a pipe is good condition with little or no defects, a spot repair may be the most suitable and cost effective method for repair. The property owner should consider a full side sewer replacement or rehabilitation if there are multiple defects throughout the pipe. It is generally less costly to hire a contractor once than to have a contractor mobilize to a site multiple times with repeated spot repairs.