ABSTRACT
Sewer rehabilitation techniques can be split into two categories. The first is the conventional method which has been used ever since the first pipe was laid underground and the technique is simple: excavate down to the defective pipe, repair it or replace it and reinstate the trench. There are times when this method is the only viable method of repair, replacement or new lay, but in congested streets it can cause significant disruption, not only to traffic but to pedestrians and shops/businesses and can have a direct impact on trade if open excavations are carried out in busy streets for long periods of time.
