A cured‐in‐place pipe (CIPP) is a trenchless rehabilitation method used to repair existing pipes. CIPP is also known as pipe lining and it is a jointless, seamless, pipe‐within‐a‐pipe with the capability to rehabilitate pipes. A resin‐saturated felt tube made of polyester is inverted or pulled into a damaged pipe. It is usually done from the upstream access point, usually where the lateral exits the home. The liner can be inflated using water or air pressure. Hot water, UV light, or steam is used to cure the resin and form a tight‐fitting, jointless and corrosion‐resistant replacement pipe.
There are several advantages to pipe lining, including a minimum amount of excavation, a potential to eliminate or reduce pavement removal and replacement costs, as well as only requiring one access point. A few disadvantages include a higher cost than open cut trench excavation in non‐pavement areas, roots and debris having to be removed from pipe before installation, and the possibility that the method might not be applicable due to collapsed or severely broken pipe, or heavy root blockages.