I’ve spent enough time around job sites to know this much:
when two contractors tell you they’re doing “the same thing,” and one price is half the other, they’re almost never doing the same thing.
CIPP pipe lining is no exception.
On paper, everything looks identical. Same acronyms. Same buzzwords. Same promises about “no digging” and “like-new pipes.” But once you get past the brochure and start looking inside the pipe, you’ll often find two very different approaches hiding behind the same label.
And the difference usually comes down to one word most people never hear until it’s too late: continuity.
What “Continuous” Actually Means (In the Real World)
A continuous CIPP liner is exactly what it sounds like — one uninterrupted, resin-impregnated tube installed over the entire length of the pipe run.
Top to bottom. Start to finish. No breaks.
Once that liner cures, robotic equipment is used to reopen each branch connection. Done correctly, you end up with a single structural pipe inside the old one — capable of standing on its own, independent of the original cast iron or clay it replaced.
That’s not marketing language. That’s how ASTM standards like F1216 and F1743 envision CIPP systems working. It’s also how most manufacturers design and warrant their products.
Is it more work?
Absolutely.
Does it require specialized equipment and trained crews?
You bet.
But it’s also the method that’s held up for decades in high-rise buildings where failure isn’t an inconvenience — it’s a catastrophe.
So What Is a “Gapped” Installation?
A gapped (or “start-and-stop”) installation uses multiple short liner segments instead of one continuous tube.
The installer drops a liner between branch connections, skips the reinstatement work, then repeats the process for the next section. The gaps are intentional. They’re not accidents. They’re part of the method.
From street level, everything still drains. Toilets flush. Showers work. Nobody complains.
For a while.
But those gaps? They’re unlined pipe. And unlined pipe is exactly what you were trying to get rid of in the first place.
Why Gaps Aren’t Just a “Small Detail”
I’ve seen plenty of buildings where gapped liners looked fine — until the structure started doing what buildings naturally do.
They move.
Wind load. Thermal expansion. Settlement. Fifty years of gravity doing its thing.
And when that happens, gaps become stress points.
Here’s what CTS routinely sees during forensic inspections:
- Moisture intrusion at unlined sections
- Cracking and separation at liner edges
- Liner migration over time
- Root intrusion at gaps
- Manufacturer warranties that don’t apply
None of that shows up on a glossy proposal. It shows up years later — usually during an inspection no one was expecting to fail.
“But It Was Approved…”
This is where things get uncomfortable.
Many gapped systems were sold as “CIPP” during a time when enforcement and documentation were inconsistent. Some were even signed off with minimal review.
That doesn’t mean they meet today’s expectations — especially under SB 4-D, SIRS investigations, or updated AHJ scrutiny.
Florida Building Code requires CIPP installations to conform to ASTM standards. ASTM standards assume continuity. Manufacturers assume continuity.
When those assumptions don’t match what’s actually in the pipe, someone eventually asks questions.
And those questions don’t go away just because the system is already installed.
The Price Difference Everyone Notices
Let’s talk about money, because that’s usually where this conversation starts.
Gapped installations are cheaper because they:
- Use less material
- Skip robotic reinstatement
- Require less equipment
- Take less time
That savings is real — on day one.
What’s not always accounted for is the long game.
When a building later discovers:
- Non-compliant liners
- Missing documentation
- Warranty exclusions
- Inspection failures
The math changes fast.
CTS has reviewed projects where buildings paid twice — once for the initial lining, and again to fix what should have been done correctly the first time.
That’s not a scare tactic. That’s a pattern.
How CTS Looks at These Systems
CTS doesn’t install liners. That’s intentional.
Our job is to look at what’s there and answer one question honestly:
Does this system do what it’s supposed to do — structurally, compliantly, and defensibly?
When we evaluate CIPP installations, we focus on:
- Liner continuity
- Installation method
- Curing indicators
- Branch reinstatement quality
- Alignment with ASTM and Florida code
If there are gaps, we document them. If the system is compliant, we confirm it. Either way, boards and engineers get facts instead of assumptions.
The Questions Worth Asking Before You Sign Anything
If you’re reviewing bids or evaluating an existing system, ask this — and don’t settle for vague answers:
- Will the liner be continuous over the entire run?
- How are branch connections handled and documented?
- What ASTM standard is being followed — specifically?
- What post-installation documentation will we receive?
- Will this hold up under a future SIRS or engineering review?
If someone gets uncomfortable with those questions, that’s usually your answer.
Final Thought
CIPP is a powerful tool when it’s done right. It can extend the life of a building, reduce disruption, and avoid massive excavation.
But “done right” isn’t a slogan. It’s a method.
And the difference between a continuous liner and a gapped one isn’t academic — it’s the difference between a system that quietly does its job for decades and one that eventually shows up in a report you weren’t hoping to read.
If you want certainty, you have to look inside the pipe.
That’s where the truth always is.