A pipe inside a pipe
Cured-in-place pipe, usually shortened to CIPP, starts as a flexible tube of felt or fiberglass fabric that is soaked with resin right before installation. The soft tube is placed inside the existing sewer lateral, pressed tight against the old pipe wall, and then hardened. Once the resin cures, the tube has become a rigid, jointless pipe that runs the length of the repair.
Because the liner takes the shape of the host pipe, the old pipe matters. Cracks, missing joint gaskets and small holes can be bridged. A pipe that has flattened, broken into loose pieces or lost its bottom entirely may not give the liner a reliable form, and that is when installers look at bursting or a spot excavation instead.
What a lining job involves
- Camera inspection.The full run is filmed to measure length, note every branch connection and judge whether the pipe is sound enough to line.
- Cleaning and descaling.Roots, grease and debris are removed. Old cast iron usually needs its tuberculation and scale ground down so the liner can sit tight and bond.
- Re-inspection.A second camera pass confirms the pipe is clean. Lining over leftover roots or scale is a common source of wrinkles and weak spots.
- Wet-out.Resin is mixed and worked into the liner tube, which is cut to the measured length.
- Installation.The liner is inverted into the pipe with air or water pressure, or pulled in and expanded with an inflatable bladder, through a cleanout or small opening.
- Curing.Depending on the system, the resin is cured with hot water, steam, UV light or at ambient temperature, while pressure holds the liner against the old wall.
- Reinstatement and final video.Any branch connections covered by the liner are cut back open from inside, and the finished line is filmed end to end.
Pipe conditions and how lining usually copes
| Condition seen on camera | Lining outlook | What to ask |
|---|---|---|
| Hairline or longitudinal cracks | Usually suitable | Will the crack be fully covered with overlap at each end? |
| Roots at joints in clay | Usually suitable after root removal | How will roots be cut and confirmed gone before lining? |
| Heavy scale in cast iron | Often suitable after descaling | How much wall is left once the scale is removed? |
| Offset joints | Depends on how far the joint has shifted | Can the liner pass the offset without folding? |
| Belly holding water | Liner follows the sag | Is the sag acceptable, or should that section be dug? |
| Collapsed or missing pipe | Generally not suitable alone | Can that spot be excavated and then lined? |
Lining at a glance
- Old pipe
- Stays in place as the host
- Diameter
- Slightly reduced by the liner's wall
- Joints
- None along the lined length
- Access
- Often a cleanout or one small opening
- Critical step
- Cleaning and descaling before install
Questions worth asking about a lining proposal
- What liner material and resin system will be used?
- How will the pipe be cleaned, and will I see the footage afterward?
- Where will the liner start and end, and how are the ends sealed?
- How many branch connections will need reinstating?
- What happens if the liner wrinkles or does not cure properly?
Common questions
Does lining make the pipe smaller?
Slightly. The liner has its own wall thickness, so the inside diameter is reduced a little. Ask the installer how the finished diameter compares with your original pipe.
Can I use the plumbing while the liner cures?
No. Drains must stay out of use during installation and curing. Ask how long your water and drains will be unavailable and plan around it.
Can a lateral be partly lined?
Yes. Short sectional or spot liners are used for a single bad joint or crack, while a full-length liner renews the whole run. The camera video helps decide which is reasonable.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.