How to Fix a Collapsed Drain: A Complete Guide

A collapsed drain is one of the most severe drainage issues a property owner can face. When a pipe loses its structural integrity and caves in, it completely blocks the flow of wastewater, leading to rapid backups, foul odors, and potential structural damage to your property.

If you suspect a collapse, immediate action is required. At CleverWorks, the first step is always a CCTV drainage survey to confirm the diagnosis. Here is a guide on how to identify a collapsed drain and how it is fixed.

Signs You Have a Collapsed Drain

Because drains are underground, a collapse isn't immediately visible. Look out for these warning signs:

• Frequent, Unexplainable Blockages: If you have your drains jetted and they block again almost immediately, the pipe may be collapsed.
• Subsidence or Sinkholes: Water leaking from a collapsed pipe washes away the surrounding soil, causing the ground above to sink or crack.
• Damp and Mold: Leaking wastewater can seep into your home's foundations, causing rising damp and mold on lower walls.
• Sewage Smells: A persistent smell of sewage inside or outside your property is a clear sign that waste is not flowing away.
• Lush Grass Patches: Sewage acts as a fertilizer. A localized patch of very green, fast-growing grass in your garden can indicate a severe leak below.

Step 1: The CCTV Drainage Survey

You cannot fix a collapsed drain without knowing exactly where the collapse is and how extensive the damage is.

A CCTV drainage survey involves feeding a camera down the pipe. When the camera reaches the collapsed section, it will be unable to pass. The engineer uses a sonde (a tracking device on the camera head) to pinpoint the exact location and depth of the collapse from above ground. This prevents unnecessary digging.

Step 2: Can it be Relined?

Many customers ask if a collapsed drain can be fixed with "no-dig" relining. The answer is almost always no.

Drain relining requires the host pipe to have some structural integrity to hold the shape of the new resin liner. If the pipe has caved in, there is no structure left to line. Therefore, excavation is required.

Step 3: Excavation and Replacement

Fixing a collapsed drain involves traditional excavation:

1. Trenching: Using the data from the CCTV survey, engineers dig a targeted trench directly above the collapsed section.
2. Removal: The shattered, collapsed pipe and any surrounding contaminated soil are carefully removed.
3. Replacement: A brand new section of durable PVC-U piping is laid down, ensuring the correct gradient (fall) is maintained so water flows freely.
4. Connection: The new pipe is securely connected to the healthy sections of the existing drainage system using specialized couplings.
5. Testing and Backfilling: The new section is tested for leaks. Once passed, the trench is backfilled with pea shingle and soil, and the surface (grass, paving, or tarmac) is reinstated.

Insurance Claims for Collapsed Drains

The good news is that accidental damage to underground services, including collapsed drains, is often covered by standard buildings insurance policies.

CleverWorks provides comprehensive, WRC-approved CCTV drainage survey reports that include video evidence, site plans, and a detailed breakdown of the required repairs. This documentation is exactly what your insurance company needs to process your claim quickly.

Suspect a collapsed drain? Don't wait for structural damage to occur. Book a CCTV drainage survey today or call CleverWorks on 01932 544 095 for emergency assistance.