Drain Relining vs Excavation: Which Repair Method Is Right?

Your CCTV drain survey has found damage. A cracked pipe, root ingress, a displaced joint, or something worse. Now you need a repair. The two main options are drain relining (a no-dig method) and traditional excavation (digging up and replacing the pipe). Both work, but they suit different situations, and the difference in cost, disruption, and time on site is significant. Here is how they compare.

What is drain relining?

Drain relining is a no-dig drain repair method. A flexible felt liner is saturated with resin, inserted into the damaged pipe from an existing access point, and inflated so it presses against the inside walls. Once the resin cures (either with ambient heat or UV light), it forms a smooth, jointless pipe within a pipe. The new lining seals cracks, bridges displaced joints, and blocks root entry points without touching the surface above.

The process typically takes three to six hours on site. No digging. No disruption to your garden, driveway, or patio. The cured liner has a design life of 50 years or more, and because it is jointless, there are no weak points for roots to exploit in the future. We carry out drain relining work every week across Birmingham and the wider West Midlands, and the majority of our domestic drain repairs use this method.

What is drain excavation?

Excavation is the traditional approach. You dig down to the damaged pipe, remove the broken section, and replace it with new pipework. In theory it is straightforward. In practice it involves heavy plant, temporary traffic management if the pipe sits under a public footpath, and reinstatement of whatever surface was above the trench, whether that is a lawn, a block-paved driveway, or a concrete path.

Excavation takes one to three days on a typical domestic job. The disruption is significant, and the reinstatement work (laying new turf, re-laying block paving, re-pouring concrete) often costs as much as the pipe replacement itself.

Drain relining vs excavation: side-by-side comparison

Here is how the two methods compare across the factors that matter most:

When is relining the better option?

Drain relining works well for the majority of domestic drain repairs. If the pipe still holds its round shape and the camera can pass through the full length, relining is almost always the better choice. These are the most common situations where we recommend it:

• Cracked or fractured pipes. Hairline cracks and longitudinal fractures in clay, concrete, or cast iron pipes. The liner seals them completely.
• Tree root damage. Roots enter through joints. The liner creates a smooth, jointless bore that roots cannot penetrate again.
• Joint displacement. Where two pipe sections have shifted apart by up to about 20mm. The liner bridges the gap and restores flow.
• Corrosion in cast iron pipes. Older cast iron soil pipes lose their internal coating over time. A resin liner restores the bore diameter and prevents further degradation.
• Pipes under structures. If the damaged section runs under a conservatory, an extension, or a shared boundary wall, excavation is often impractical or impossible. Relining avoids the problem entirely.

We carry out no-dig drain repairs across Birmingham and the wider West Midlands, including areas with older housing stock like Northfield and Bartley Green, where ageing clay pipes and tree root problems are particularly common.

When is excavation the only option?

Relining cannot fix everything. In some cases, digging up and replacing the pipe is the only realistic option:

• Complete pipe collapse. If the pipe has lost its shape entirely and soil has entered the drain, there is nothing for a liner to bond to. The collapsed section needs to be removed and replaced.
• Severe belly or sag. A bellied section is where the pipe dips and traps standing water. Relining follows the shape of the existing pipe, so it will not correct the sag. Excavation allows the pipe to be re-laid at the correct gradient.
• Major displacement. If two pipe sections have shifted apart by more than about 25mm, the liner cannot bridge the gap reliably. Excavation and reconnection is the safer repair.
• Change in pipe diameter. If the run changes from 100mm to 150mm at a junction, a liner cannot transition between the two sizes. The junction needs to be excavated and rebuilt.

How much does each method cost?

The drain relining cost for a standard domestic section (typically 3 to 6 metres of 100mm pipe) runs between £380 and £1,200. The price depends on the liner diameter, the length of the section, and whether UV curing or ambient curing is used.

Excavation is more expensive because you are paying for plant hire, labour, disposal of the old pipe, new materials, and surface reinstatement. A typical domestic excavation repair costs between £1,000 and £4,000 or more, depending on depth, access, and what sits above the trench. If the pipe runs under a tarmac driveway, the reinstatement alone can cost £500 to £1,500 on top of the pipe work.

We always start with a CCTV survey before recommending either method. The camera footage shows us exactly what we are dealing with, so we can give you an accurate fixed-price quote for the repair. No guesswork, no surprises. We cover properties across the West Midlands, from Bromsgrove and Walsall to Wolverhampton and beyond.

Questions about drain repairs

What is drain relining?

Drain relining is a no-dig repair method where a resin-coated felt liner is inserted into a damaged pipe and inflated. Once the resin cures, it forms a smooth, jointless pipe within a pipe that seals cracks, root damage, and minor joint displacement without any excavation.

How much does drain relining cost compared to excavation?

Drain relining typically costs between £380 and £1,200 per section, depending on the pipe diameter and length. Excavation costs between £1,000 and £4,000 or more, because it involves digging, removing the old pipe, laying a replacement, and reinstating the surface above.

How long does drain relining last?

A properly installed resin liner has a design life of 50 years or more. The cured liner is resistant to root ingress, chemical corrosion, and joint displacement, so it typically outlasts many of the original pipe materials it is installed inside.

When should you excavate instead of reline?

Excavation is the better option when a pipe has completely collapsed, when there is a severe belly or sag in the line that traps standing water, when the pipe has displaced so far that the liner cannot bridge the gap, or when the pipe diameter changes at a junction.