Pipe coating — also called pipe lining or cured-in-place pipe (CIPP) lining — is a trenchless method of rehabilitating damaged or deteriorated pipes from the inside without excavating the ground above them. A flexible liner saturated with resin is inserted into the existing pipe, pressed against the pipe walls, and cured in place to form a smooth, jointless new surface inside the old one. The result is a structurally sound pipe within a pipe, often extending the line’s service life by decades.

How the Process Works

Before lining begins, the pipe is cleaned — typically with hydrojetting to remove root intrusion, scale, grease, and debris — and inspected with a camera to assess the extent of damage and confirm the pipe is a good candidate for lining. If the pipe has collapsed sections or major structural failures, lining may not be appropriate and spot repair or full replacement becomes the better path.

Once the pipe is clean and mapped, a flexible tube impregnated with epoxy or polyester resin is pulled or inverted into the pipe. An inflatable bladder expands the liner outward, pressing the resin-soaked material firmly against the host pipe walls. Heat, UV light, or ambient temperature — depending on the resin system used — cures the liner over several hours. When curing is complete, the bladder is removed and the new liner, now bonded to the interior of the old pipe, forms a seamless, corrosion-resistant surface.

Why Pipe Coating Matters in Denver

Denver’s older neighborhoods — particularly homes built between the 1950s and 1980s — commonly have clay, cast iron, or Orangeburg sewer laterals that have spent decades being stressed by Colorado’s expansive clay soils. These soils shift significantly with moisture changes and freeze-thaw cycles, and they’re hard on buried pipes. Root intrusion from mature trees along parkways and sidewalk strips compounds the problem by finding every joint and crack in an aging lateral.

Digging up a sewer lateral under a driveway, landscaped yard, or patio is disruptive and expensive. Pipe lining solves the same structural problem at a fraction of the excavation cost and with far less surface disruption. In many cases the entire lateral can be lined in a single day with the homeowner’s yard left intact.

What Pipe Lining Can and Cannot Fix

  • Cracks and fractures in the pipe wall
  • Root intrusion through joints and cracks
  • Corrosion and deterioration on cast iron or clay pipe
  • Minor joint offsets where the pipe still holds its basic shape
  • General deterioration that would otherwise require full replacement

Pipe coating is not appropriate for pipes with complete collapses, severe deformation, or sections where the pipe has separated too severely to hold a liner in position. Camera inspection before any lining project is how these determinations are made — and it’s also how Done confirms that lining is the right solution for your specific situation rather than recommending it blindly.

The Interior Diameter Trade-Off

Lining slightly reduces the interior diameter of the pipe — typically by a few millimeters depending on liner thickness. In most cases this has no meaningful effect on flow capacity; the smooth interior surface of the liner actually improves flow compared to a rough, root-infested, or scale-coated original pipe. For small-diameter pipes in very poor condition, this is a reasonable trade-off for decades of renewed service life.

Common Applications

Sewer laterals — the pipes that run from your home to the municipal main — are the most common target for residential pipe lining in the Denver area. But lining is also applied to drain lines inside buildings, storm drain systems, and in some cases aging water mains. For homeowners, the conversation is almost always about the sewer lateral connecting to the city main at the street.

If a camera inspection has revealed cracking, root intrusion, or deterioration in your sewer line, pipe lining is worth discussing as an alternative to full excavation. Done’s team handles trenchless pipe lining throughout the Denver metro. Learn more on our pipe lining page, or visit our sewer services page for the full range of drain and sewer solutions available.