How Does Pipe Relining Work? (The No-Dig Solution Explained)

Got cracked, leaking, or tree-root-invaded pipes? Twenty years ago your only option was digging up the yard, tearing up driveways, and replacing everything from scratch. Today there’s a better way: pipe relining — a trenchless technology that repairs your pipes from the inside without excavation.

Pipe relining has become one of the most popular plumbing solutions in Melbourne, and for good reason. It’s faster, less disruptive, often cheaper, and the result is a new pipe-within-a-pipe that can last 50 years or more.

This guide explains exactly how the process works, what it costs, when it’s the right choice, and how to find a qualified relining specialist in Melbourne.

What Is Pipe Relining?

Pipe relining is a trenchless pipe repair method that creates a new, seamless pipe inside your existing damaged pipe. Instead of digging up and replacing the old pipe, a flexible resin-saturated liner is inserted into the damaged pipe, inflated to press against the pipe walls, and then cured (hardened) to form a rigid new pipe within the old one.

Think of it like putting a new pipe inside the old one — without removing the old one. The result is a smooth, jointless, corrosion-resistant pipe that restores full flow capacity and eliminates cracks, leaks, and root intrusion points.

The technology has been used in large-scale municipal infrastructure for decades but has become increasingly accessible for residential and small commercial applications over the past 10–15 years. Modern relining materials — typically epoxy resin with a fibreglass or felt liner — are extremely durable and are backed by warranties of 35 to 50 years from most providers.

The Pipe Relining Process — Step by Step

While techniques vary slightly between providers and pipe types, the core relining process follows these six stages:

Step 1: CCTV pipe inspection

Every relining job starts with a CCTV drain camera inspection. A small, high-definition camera is fed through the pipe system to identify the exact location, nature, and extent of the damage. The technician records video footage of the entire pipe, noting cracks, fractures, root intrusion, displaced joints, corrosion, and any blockages.

This inspection serves two purposes: it confirms that relining is the right solution (not every pipe problem can be relined), and it provides the measurements needed to prepare the liner — including pipe diameter, length, and the number and location of junction points.

The CCTV inspection typically takes 30 minutes to an hour for a standard residential property.

Step 2: Pipe cleaning and preparation

Before the liner can be installed, the pipe must be thoroughly cleaned. Any debris, tree roots, scale, grease buildup, or obstructions need to be removed to ensure the liner bonds properly to the pipe wall.

Cleaning methods include:

• High-pressure water jetting — the most common method. A specialised nozzle blasts water at pressures up to 5,000 PSI to strip the pipe walls clean.
• Robotic cutting — for stubborn root intrusions or hardened deposits that water jetting alone can’t remove. A robotic cutting head is sent into the pipe to mechanically remove obstructions.
• Chain flails or descaling tools — used for heavily corroded cast iron or steel pipes where scale has significantly reduced the pipe diameter.

Thorough cleaning is critical. A poorly prepared pipe surface will result in poor liner adhesion and a shorter lifespan for the repair.

Step 3: Liner preparation

While the pipe is being cleaned, the relining team prepares the liner. This involves:

• Cutting the liner material (typically a felt or fibreglass sleeve) to the exact length and diameter of the section being relined
• Saturating the liner with a two-part epoxy resin. The resin is carefully mixed and applied to ensure complete, even coverage
• Rolling the resin-impregnated liner onto an inflatable bladder (for inversion lining) or preparing it for pull-in-place installation

The type and thickness of the liner is selected based on the pipe diameter, the extent of damage, and the structural requirements. Pipes with more severe damage may require a thicker liner for additional strength.

Step 4: Liner insertion

The prepared liner is inserted into the damaged pipe using one of two main methods:

• Inversion method — the liner is turned inside-out using air or water pressure, pushing it through the pipe from an access point (usually a drain cleanout, manhole, or small excavation). As it inverts, the resin-coated side presses against the pipe wall.
• Pull-in-place method — the liner is pulled through the pipe using a cable and winch system, then inflated with a bladder to press it against the pipe wall. This method gives more control over positioning and is often used for shorter sections or junction repairs.

In both cases, the inflated liner is pressed firmly against the existing pipe wall, conforming to its shape and filling any cracks, gaps, or root entry points.

Step 5: Curing

Once the liner is in position, it needs to cure (harden). Curing methods include:

• Ambient cure — the resin hardens naturally over several hours at room temperature. Simpler but slower — typically 4 to 12 hours depending on conditions.
• Hot water cure — hot water is circulated through the bladder to accelerate the curing process. Reduces cure time to 2 to 4 hours.
• UV cure (ultraviolet light) — a UV light train is pulled through the liner, curing the resin almost instantly. This is the fastest method (often under an hour) and produces very consistent results. Increasingly common for larger diameter pipes.
• Steam cure — steam is used to heat and cure the resin. Common in larger municipal applications.

During curing, the bladder remains inflated to maintain pressure against the pipe wall until the resin has fully hardened.

Step 6: Final inspection

After curing, the bladder is deflated and removed. Any junction connections that were covered by the liner are reopened using a robotic cutter. A final CCTV inspection is then conducted to verify:

• The liner is properly positioned with no wrinkles, folds, or defects
• All junctions are open and flowing correctly
• The repair is complete and watertight

The technician will typically provide you with before-and-after CCTV footage showing the condition of the pipe pre- and post-relining. This footage also serves as documentation for your warranty.

Pipe Relining vs Traditional Pipe Replacement

How does relining stack up against traditional dig-and-replace methods? Here’s a direct comparison:

Factor	Pipe Relining	Traditional Replacement
Excavation required	Minimal to none	Full trench along pipe length
Disruption to property	Low — gardens, driveways, and structures stay intact	High — significant landscaping and surface damage
Typical cost (residential)	$3,500 – $15,000	$5,000 – $25,000+
Time to complete	1 – 2 days (most residential jobs)	3 – 7 days or more
Lifespan of repair	50+ years (warranty typically 35–50 years)	50–80 years (new PVC or clay pipe)
Pipe diameter after repair	Slightly reduced (liner thickness ~5–6mm)	Full original diameter or larger
Suitable for all damage types	Most — not all (see limitations)	Yes — any damage, any pipe
Restoration costs	Minimal	Significant — driveways, landscaping, concrete
Environmental impact	Lower — less waste, less disturbance	Higher — excavation, old pipe disposal, backfill

For most residential situations in Melbourne, relining wins on cost, speed, and convenience — particularly when pipes run under driveways, concrete slabs, established gardens, or the house itself. Traditional replacement makes more sense when pipes have completely collapsed, are severely misaligned, or when the diameter reduction from a liner would cause flow issues.

What Pipes Can Be Relined?

Modern relining technology is surprisingly versatile. Most common pipe types found in Melbourne homes can be relined:

• Clay (terracotta) pipes — extremely common in Melbourne, especially in homes built before the 1980s. Clay pipes are prone to cracking, root intrusion at joints, and displacement. They’re excellent candidates for relining.
• PVC pipes — less commonly relined (they’re already relatively durable), but cracked or broken PVC sections can be relined successfully.
• Cast iron pipes — common in older homes for internal drainage and vent stacks. Cast iron corrodes over time and is well-suited to relining.
• Concrete pipes — typically found in stormwater and larger sewer lines. Can be relined with appropriate liner specifications.
• Earthenware pipes — similar to clay, common in very old Melbourne properties. Can be relined provided the pipe hasn’t collapsed.
• Steel and galvanised pipes — can be relined, though heavily corroded sections may need descaling first.

Pipe diameters

Residential relining is most commonly performed on pipes from 50mm to 300mm in diameter. This covers standard household drain pipes (100mm), sewer connections (150mm), and stormwater lines (up to 225–300mm). Larger diameters are relined for commercial and municipal applications.

When Pipe Relining Isn’t Suitable

Relining is an excellent solution for most pipe problems, but it’s not suitable in every situation:

• Completely collapsed pipes — if the pipe has fully collapsed or lost its shape, there’s nothing for the liner to sit against. The pipe needs to be excavated and replaced.
• Severely misaligned or bellied pipes — if sections of pipe have dropped or shifted significantly (creating a “belly” where water pools), relining will follow the same profile and the pooling issue will persist. Excavation and re-grading is needed.
• Back-to-back bends or sharp angles — the liner needs a reasonably straight path to be inserted and inflated properly. Multiple tight bends in succession can make insertion impossible.
• Extremely deteriorated pipes — if the pipe wall has corroded to the point where it can’t support the liner during curing, relining may not provide a stable result.
• Very small diameter pipes — pipes under 40mm are generally too small for practical relining, as the liner would reduce the diameter excessively.
• Pipes with no access point — relining requires at least one access point (drain cleanout, inspection opening, or manhole). If no access exists and one can’t be created without major excavation, the cost advantage of relining is reduced.

A reputable relining company will tell you upfront during the CCTV inspection if relining isn’t the right solution for your situation. Be wary of anyone who says they can reline everything — some honesty about limitations is a sign of a good operator.

Pipe Relining Costs in Melbourne

Relining costs in Melbourne vary based on pipe diameter, length, access, and the severity of the problem. Here are typical price ranges for 2026:

Job Type	Typical Cost
CCTV inspection (standalone)	$250 – $500
Single section reline (1–3 metres)	$2,000 – $4,500
Standard residential reline (3–10 metres)	$4,000 – $10,000
Full property sewer reline (10–20 metres)	$8,000 – $18,000
Junction repair (per junction)	$800 – $2,000
Patch repair (localised, under 1 metre)	$1,500 – $3,000
Stormwater pipe reline (larger diameter)	$5,000 – $15,000+

These prices include the CCTV inspection, cleaning, liner installation, curing, final inspection, and warranty. Some companies charge the initial CCTV inspection separately (typically $250–$500) and credit it against the relining cost if you proceed.

How Long Does Pipe Relining Take?

One of relining’s biggest advantages is speed. Here’s what to expect:

Job Scope	Typical Duration
Single section / patch repair	4 – 8 hours (same day)
Standard residential (one line)	1 day
Multiple lines / complex residential	1 – 2 days
Commercial or multi-unit	2 – 5 days

After curing, the pipe is typically ready for use immediately or within a few hours, depending on the curing method used. UV-cured liners are ready almost instantly; ambient-cured liners may need overnight before the system is put back into service.

Compare this to traditional pipe replacement, which often takes 3–7 days for the plumbing work alone — plus additional time for excavation and reinstatement.

Residential vs Commercial Pipe Relining

While the core technology is the same, residential and commercial relining projects differ in scale, complexity, and requirements:

Residential relining

• Typically involves 100–150mm diameter pipes (sewer and stormwater)
• Standard runs of 5–20 metres
• Access usually via existing cleanouts or small excavations
• Completed in 1 day for most jobs
• Common issues: tree root intrusion, cracked clay pipes, displaced joints

Commercial relining

• Larger diameter pipes (150mm–600mm+) and longer runs
• May involve grease trap connections, industrial waste lines, and stormwater infrastructure
• Often requires traffic management, after-hours work, and coordination with building management
• May need engineering sign-off and compliance documentation
• Multi-day projects are common for larger buildings

For commercial properties, relining is particularly valuable because it minimises business disruption. A restaurant, office building, or retail centre can continue operating while relining work is carried out — something that’s rarely possible with traditional excavation methods.

Choosing a Pipe Relining Company in Melbourne

Pipe relining is a specialised trade. Not every plumber offers it, and quality varies significantly between providers. Here’s what to look for:

• Licensed plumber — all pipe relining work in Victoria must be performed by or under the supervision of a licensed plumber. Check their licence with the Victorian Building Authority (VBA).
• Relining-specific experience — ask how many relining jobs they’ve completed and how long they’ve been offering the service. Relining requires specialised equipment and training beyond standard plumbing.
• Quality materials — ask what brand and type of liner they use. Reputable brands include Brawoliner, Brandenburger, and Picote. Avoid companies that are vague about their materials.
• Warranty — most reputable providers offer a 35 to 50-year warranty on the liner itself. Get the warranty in writing, and check what it covers (materials, labour, or both).
• CCTV before and after — any professional relining company should provide CCTV footage of the pipe before and after the work. This is standard practice and provides documentation of the repair.
• Transparent pricing — get a written quote with a clear scope of works. Be wary of companies that quote per metre without inspecting the pipe first — the final cost can blow out.
• Insurance — confirm they hold adequate public liability insurance and plumber’s warranty insurance.

Maintenance After Pipe Relining

One of the benefits of a relined pipe is that it requires very little maintenance. The smooth, jointless interior surface resists root intrusion and buildup far better than the original pipe. However, there are a few things you can do to maximise the lifespan of your relined pipes:

• Don’t plant large trees near sewer lines — while the relined pipe is far more resistant to root intrusion than the original, roots can still find their way in over time if given the opportunity. Keep large trees and aggressive species (willows, poplars, fig trees) well away from your sewer line.
• Avoid flushing inappropriate items — wet wipes, sanitary products, cooking fats, and other non-flushable items can cause blockages in any pipe. Treat your relined pipe the same as you would a new pipe.
• Schedule periodic CCTV inspections — a quick camera check every 5–10 years can catch any issues early. Some relining companies include periodic inspections as part of their warranty service.
• Address drainage issues promptly — if you notice slow drainage, gurgling, or odours after relining, contact your relining company promptly. Warranty repairs are much easier when issues are caught early.

With proper care, a quality reline should last 50 years or more — effectively the remaining useful life of most residential properties.

Frequently Asked Questions